The next version of ASP.NET (“ASP.NET  vNext”) has been redesigned from the ground up. 
The goal is to create a lean and composable .NET  stack for building modern cloud-based  apps. 
You don't have to use Visual Studio to develop ASP.NET vNext  applications. 
You can develop and run vNext on platforms that  Visual Studio doesn't run on. 
Few New Releases:
1.        .NET Compiler Platform ("Roslyn")
2.       .NET Next Generation  JIT (“RyuJIT”).
Introduction to ASP.NET vNext
    Here are some of the new features in ASP.NET  vNext.
ASP.NET vNext includes updated versions of MVC,  Web API, Web Pages, SignalR and EF - ASP.NET  vNext (MVC, Web API and Web Pages 6; EF 7; SignalR 3)
Intro:
    - ASP.NET vNext includes updated versions of MVC, Web       API, Web Pages, SignalR and EF. 
 
The  key improvement with these frameworks is that MVC, Web API and Web Pages have  been merged into a single  programming model. For example, there’s now unified controller and  routing concepts between all three. You can now have a single controller that  returns both MVC views and formatted Web API responses, on the same HTTP verb. 
- ASP.NET vNext apps are cloud ready by design. Services such as       session state and caching adjust their behavior depending on whether the       app is running in the cloud or in a traditional hosting environment, while       providing a consistent API. 
 
- We use dependency injection behind the scenes to provide your app       with the correct implementation for these services. 
 
Using  this approach, it is really easy to move your app from on-premises to the  cloud, since our code changes, not yours.
- You will be able to make changes to your web       applications and see the results after a browser refresh, with no separate build step       needed. This significant productivity enhancement is based on improvements       to load times in the underlying CLR, as well as use of the new .NET Compiler Platform       ("Roslyn").       
 
Rebuilt from the Ground Up
    - MVC, Web API,       and Web Pages are       merged into one framework, called MVC 6. The new framework uses a common set of abstractions       for routing, action selection, filters, model binding, and so on. 
 
I.e.  There’s now unified  controller and routing concepts between all three. You can now have a single controller that returns  both MVC views and formatted Web API responses, on the same HTTP verb.
- Dependency injection is built into the framework. Use       your preferred IoC container to register dependencies.
 - vNext is host agnostic. You can host your app in IIS,       or self-host in a custom process. (Web API 2 and SignalR 2 already support       self-hosting; vNext brings this same capability to MVC.)
 - vNext is open source and cross platform.
 
Leaner, Faster
    - MVC 6 has no dependency on System.Web.dll. The       result is a leaner framework, with faster startup time and lower memory       consumption.
 - vNext apps can use a cloud-optimized runtime       and subset of the .NET Framework. This subset of the framework is about 11 megabytes in size       compared to 200 megabytes for the full framework, and is composed of a       collection of NuGet packages.
 - Because the cloud-optimized       framework is a collection       of NuGet packages, your app can include only the packages you       actually need. No unnecessary memory, disk space, loading time, etc.
 - Microsoft can deliver updates to the       framework on a faster cadence, because each part can be updated       independently.
 
True Side-by-Side Deployment
    The reduced footprint of the cloud-optimized  runtime makes it practical to deploy the framework with your app. 
- You can run apps side-by-side with different versions of the       framework on the same server.
 - Your apps are insulated from framework changes on the       server.
 - You can make framework updates for each app on its own       schedule.
 - No errors when you deploy to production resulting from       a mismatch between the framework patch level on the development machine       and the production server.
 
New Development Experience
    vNext uses the Roslyn compiler  to compile code dynamically. 
- You can edit a code file, refresh the browser, and see       the changes without rebuilding the project. 
 - Besides streamlining the development process, dynamic code compilation       enables development scenarios that were not possible before, such as       editing code on the server using Visual       Studio Online ("Monaco").
 - You can choose your own editors and tools.
 
ASP.NET vNext is being rewritten from the ground  up, and while much of your code for vNext will look the same.
vNext is not backwards compatible with existing ASP.NET  applications. 
However, the current frameworks (Web Forms 5,  MVC 5, Web API 2, Web Pages 3, SignalR 2, and Entity Framework 6) will continue  to ship in Visual Studio, and will be fully supported in ASP.NET vNext. 
Summary:
The table below  outlines the ASP.NET vNext scenarios we’ve built and where they are  available.
|      ASP.NET    vNext Feature  |          On    .NET vNext  |          On    .NET vNext (Cloud Optimized)  |    
|      Cloud Ready  |          *  |          *  |    
|      Modular Design  |          *  |          *  |    
|      Dependency    Injection  |          *  |          *  |    
|      Consistent    Tracing / Debugging  |          *  |          *  |    
|      Faster    Development (browser refresh)  |          *  |          *  |    
|      Open Source  |          *  |          *  |    
|      Full Side by    Side (runtime and framework   |             |          *  |    
|      Faster    startup, Lower memory / Higher throughput (best of class)  |             |          *  |    
|      Uses a smaller    set of framework libraries  |             |          *  |    
|      Enabled on    Mono, on Mac and Linux  |             |          *  |    
ASP.NET vNext will be open source and  will be contributed to the .NET  Foundation. This shouldn’t come as a big surprise since the ASP.NET Web stack is already  open source. All of ASP.NET vNext will be delivered via NuGet, will be open  source and will take contributions. Read ASP.NET  vNext: the future of .NET on the Server to learn more.
Our announcement at TechEd is the first  stop for .NET vNext and ASP.NET vNext. We’ll share much more in the  months to come before we release the final versions. We’re looking  forward to shipping pre-release versions in order to get your feedback.
Code View:
    project.json
The  project.json file contains a list of dependencies for the project and a list of  build output configurations. 
It  can also include a list of commands.
The  project.json file also specifies build output framework configuration options.
{
    "dependencies": {
         "Microsoft.AspNet.Server.IIS" : "1.0.0-alpha3",
                                "Microsoft.AspNet.Mvc":  "6.0.0-alpha3",
                                "Microsoft.AspNet.Identity.EntityFramework":  "3.0.0-alpha3",
         "Microsoft.AspNet.Identity.Authentication": "3.0.0-alpha3",
        "Microsoft.AspNet.Security.Cookies":  "1.0.0-alpha3",
         "Microsoft.AspNet.Server.IIS": "1.0.0-alpha3",
         "Microsoft.AspNet.Server.WebListener": "1.0.0-alpha3",
         "Microsoft.AspNet.StaticFiles": "1.0.0-alpha3",
         "Microsoft.Framework.ConfigurationModel.Json":  "1.0.0-alpha3",
         "Microsoft.VisualStudio.Web.BrowserLink.Loader":  "14.0-alpha2",
         "Classlibrary1": ""
    }
   "frameworks": {
        "net45": {  },
        "k10": { }
    }
}
Commands
The  project.json file can also contain commands that facilitate running the  application from the command line. 
For  example:
{
    "commands": {        
        "web":  "Microsoft.AspNet.Hosting --server Microsoft.AspNet.Server.WebListener  --server.urls http://localhost:5000"
    }
}
Startup.cs
By  default, the vNext hosting environment expects to find a startup class named  Startup. 
This  class must contain a Configure method that takes an IBuilder parameter, and you  configure the HTTP pipeline inside this Configure method. The empty project  creates the class with nothing in the Configure method. 
using System;
using Microsoft.AspNet.Builder;
using Microsoft.Framework.DependencyInjection;
namespace HelloWorld
{
    public class Startup
    {
        public void  Configure(IBuilder app)
        {
           app.UseServices(services  =>
             {
                 services.AddMvc();
             });
             app.UseMvc();
        }
    }
}
Here  - AddMvc method adds the MVC framework services to the dependency  injection system. 
The  UseMvc method configures MVC default settings such as routes.
Config.json - vNext  configuration
The  template creates a config.json file to store application settings such as  database connection strings:
{
    "Data": {
         "DefaultConnection": { 
             "ConnectionString":  "Server=(localdb)\\mssqllocaldb;Database=aspnetvnext-HelloWorld2-f0652fd2-febf-488d-955b-b4c590e536f1;Trusted_Connection=True;MultipleActiveResultSets=true"
        }
    }
}
References:
http://www.asp.net/vnext/overview/aspnet-vnext/getting-started-with-aspnet-vnext-and-visual-studio
http://blogs.msdn.com/b/dotnet/archive/2014/05/12/the-next-generation-of-net-asp-net-vnext.aspx
http://blogs.msdn.com/b/webdev/archive/2014/08/12/develop-asp-net-vnext-applications-on-a-mac.aspx
Hope this helps.
Regards,
Arun Manglick
