Fix an inadvertent 204 in activator tests

On a web server, this test ends up giving back a 204 because of the MVC
behavior when an action is declared to return void. The fix is to use
EmptyResult.
Adding a pattern for returning 'unhandled' exception information via
middleware.

This should be used where posssible instead of throwing an exception and
catching in a test, as that only works in memory.
Changed hard coded argument string in the throw to use nameof
Adding functional test for RazorViewEngineOptions.FileSystem
Bug #1354 - ViewComponent View() fails on CoreCLR with IEnumerable<> passed in.
Fix - When the model is passed in to a View, ViewDataDictionary sets it. During this process, we recurse through all the properties and create FastPropertyGetters for each of them. In this case, since it is an enumerable, the properties which we recurse through are not the elements of the collection but the properties of the Enumerable instead. i.e - Enumerable.Current. Creating getters for these properties are not necessary. The fix moves the property iteration step to a place where the properties are actually requested.
- Splitting TypeInformation class into two and separating their caches appropriately.
Adding additional functional tests for ModelBinding
Fixed folder name casing of Compiler/*
Merge branch 'release' into dev
Update Mvc to use official xunit runner
Updating Razor to not use K.Roslyn
Merge branch 'release' into dev
added few taghelper functional tests
Logging assemblies, controllers, and actions
Reacting to FileSystem changes
Reacting to FileSystem changes v2
React to aspnet/Razor#207 changes.
Modify TagHelpers to use new content mode design.

- React to aspnet/Razor#221
- Modified existing TagHelpers to no longer rely on ContentBehavior and to instead utilize GetChildContentAsync, PreContent, Content and PostContent.
Modify TagHelper tests to abide by new content mode design.

- React to aspnet/Razor#221
- Modified existing TagHelper tests to no longer rely on ContentBehavior.
- Updated signatures of TagHelperExecutionContext and TagHelperContext pieces.