[Fixes #1156] EmptyResult should not set status code (or do anything for that matter)
Renamed configurations to frameworks in project.json
Making UrlHelper's methods virtual
Create a pre compilation module and apis to allow meta programming
to precompile razor pages.

This is limited to sites where the .cshtml are still deployed. It's
current purpose is to speed up startup. Deploying without the razor
files is a separate feature.
Adding Api Explorer
Don't close the stream when reading AssemblyMetadata
Convert memory streams to the byte[] before passing it to roslyn
[Fixes #926] Protocol & Host name ignored when creating action link
Removed primary ctor usage
Use CodeBuilderContext instead of CodeGeneratorContext.
Use Microsoft.AspNet.Razor.Runtime project.
Configure host to utilize tag helper types.

- Set the appropriate GeneratedTagHelperContext properties to ensure code is generated correctly.
- Added a new service dependency to the MvcRazorHost to take in ILibraryManager so it can create a valid TagHelperDescriptorResolver.

#1165
Add writing scopes to RazorPage.

- RazorPage now has the ability to use writing scopes to control where things are written.
- This enables RazorPages to use these writing scopes with TagHelpers.  TagHelpers use them to buffer attributes that have C# contained within them and to also buffer content of TagHelpers whos ContentBehavior is Modify.
- Added RazorPage tests to validate their functionality.

#1102