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
Improve XML comments in `HtmlHelper` and related classes and interfaces
- #847 line 1: copy XML comments from interfaces to extension methods
- lots of wording changes to be more consistent
 - core text split from PR #866, where @rynowak and I hashed out the words
 - to extent possible, reuse words between method descriptions

- add `<remarks>` describing behaviour of input helpers e.g. `CheckBox()`
- add a few missing `<param/>` and `<typeparam/>` elements and fill in empty ones
- display more HTML elements as tags
- use `<c>true|false|null</c>` more often

nits:
- "The expression" -> "An expression"
- make examples for `ObjectToDictionary()` and `AnonymousObjectToHtmlAttributes()` more consistent
- move `<typeparam/>` elements (that existed) after all `<param/>` elements
Address PR comments
- one more dictionary -> `<see cref="IDictionary{string, object}"/>` case (repeated a few times)
- add remarks explaining "renders"
- explain "checked" attributes better, removing some duplicated words from the `RadioButton[For]()` descriptions

nit: correct `routeValues` description in `GenerateForm()` comments