Fix Challenge params order.
Correct gaps in PR #934
- correct XML comment typo introduced in `HtmlHelper` in 56d66c090eaedc33e4838437e7611ba2b9ca8929 (bad merge)
- fix missed `null` requirement for `@Html.RadioButtonFor()` and remove buried `null` check
- add back `Environment.Newline` to `@Html.TextArea()` (was dropped though comment wasn't)
Simplify some XML comment references
- follow VS fixup suggestion and change e.g. `<see cref="System.String"/>` -> `<see cref="string"/>`
Propogate additional compilation data from RoslynCompilationService
* Update CompilationFailedException to include path of file being compiled
* Pass in path being compiled to Rolsyn.
* Adding doc comments for compilation pieces

Fixes #869
Removing AdditionalInfo from CompilationResult since we can't always pass
it into exception thrown

All values in Exception.Data need to be serializable which is not true for
the diagnostics. Removing this property since we can't pass it through.
Fixing unit test
Data Token support changes
Reverting changes to sln file made in 01f5fec210ea864f8ed3637d775c4dc1a433524f
Making RoslynCompilationService a singleton.
 * Minor code cleanup from previous compilation related PR.
Test for XML documentation errors
- extend the "test" target in our build to use new k-xml-docs-test.shade command

Example output with one syntax error and one invalid reference:
```
info: Target xml-docs-test
warn: Invalid documentation syntax in src\Microsoft.AspNet.Mvc.Core\bin\debug\net45\Microsoft.AspNet.Mvc.Core.xml
warn:   3170: <!-- Badly formed XML comment ignored for member "T:Microsoft.AspNet.Mvc.Rendering.HtmlHelper" -->
warn:   3203: If the object is already an <see cref="!:IDictionaries&lt;string, object&gt;"/> instance, then it is
```
ProducesAttribute +
Adding Functional Tests

Conflicts:
	src/Microsoft.AspNet.Mvc.Core/Formatters/OutputFormatter.cs
	src/Microsoft.AspNet.Mvc.Core/Resources.resx
	src/Microsoft.AspNet.Mvc.HeaderValueAbstractions/project.json
	test/Microsoft.AspNet.Mvc.FunctionalTests/project.json

Adding Resources + tests

Conflicts:
	src/Microsoft.AspNet.Mvc.Core/Properties/Resources.Designer.cs
	src/Microsoft.AspNet.Mvc.Core/Resources.resx

Adding produces content Attribute

Conflicts:
	src/Microsoft.AspNet.Mvc.Core/Microsoft.AspNet.Mvc.Core.kproj

Conflicts:
	src/Microsoft.AspNet.Mvc.Core/Microsoft.AspNet.Mvc.Core.kproj
	test/Microsoft.AspNet.Mvc.Core.Test/Microsoft.AspNet.Mvc.Core.Test.kproj
Introducing Activator for ViewComponents.
Addressing some PR comments.