Fixing a typo in the MarkerAwareValueProvider name. Also removing additional registration of IValueProviderFactoryProvider from
services.
Add WebRoot node to project.json on MvcSample.Web
[Fixes #1201] Handle virtual paths in FilePathResult
IServiceProvider.GetService now returns null for missing services

Previously GetService would throw if the requested service was missing.
This commit updates MVC to account for the change in behavior.
Replace calls to GetService<T> with GetRequiredService<T>

Even though GetService<T> still exists, GetRequiredService<T> preserves
the old behavior of throwing for missing services.
Split line made over 120 chars by call to GetRequiredService
Add `DefaultEditorTemplates.MultilineTemplate`
- #965
- test call-throughs from `Html.Editor[For]()` to inner `IHtmlHelper`
 - add another parameter to `DefaultTemplatesUtilities.GetHtmlHelper()`

nit: reorder dictionaries at the top of `TemplateRenderer` slightly
Issue #1206 - DefaultBodyModelValidator throws if get accessor throws.
Fix: The MvcOptions takes in a list of ExcludeFromValidationDelegate (Func<Type,bool>). This func verifies if the type is excluded in validation or not.
Fixing a few comments relating to DefaultBodyModelValidator.
[Fixes #1332] Port IContentNegotiator to WebAPI shim for CoreCLR support

1. Ported IContentNegotiator.
2. Enabled Core CLR configuration
Fix for item #1278 - Add WebAPI ActionResult types and helper methods on
ApiController

Ports all of the WebAPI action result types.
Add TagHelperSample.Web
Add `IHtmlGenerator` and its default implementation
- part of #1243 (kind-of)
- mostly copied from `HtmlHelper` but refactored to
 - consistently take a `ViewContext` parameter and return a `TagBuilder`
 - provide `GenerateActionLink()` and `GenerateRouteLink()`
 - provide a separate `GenerateHiddenForCheckBox()`, allowing
   `GenerateCheckBox()` to return a `TagBuilder`
 - `GenerateForm()`'s `method` parameter is a `string`, not `FormMethod`

nits: format document, consistent line wrapping, variable name changes, ...
Add `IHtmlGenerator` to DI and enable MVC tag helpers in TagHelperSample.Web
- also fix a couple of minor issues in TagHelperSample.Web
Add `TextAreaTagHelper` and Microsoft.AspNet.Mvc.TagHelpers project
- rest of #1243 and all of #1244
- needs a few utility methods for copying `TagBuilder` to `TagHelperOutput`
 - but works as-is
Add tests of `TextAreaTagHelper`
- new Microsoft.AspNet.Mvc.TagHelpers.Test project
- bit of test infrastructure -- `TestableHtmlGenerator`
 - short-curcuits validation attribute and AntiForgery additions
 - should help when testing all MVC tag helpers
Update `HtmlHelper` to use `IHtmlGenerator`
- make a few more methods available as `internal static` in `DefaultHtmlGenerator`
 - remove `IHtmlGenerator.GenerateOption()`; now `internal static`

nits:
- add `IHtmlGenerator.IdAttributeDotReplacement`
- move `DefaultHtmlGenerator.IdAttributeDotReplacement` after constructor
- move `HtmlHelper.ActionLink()` below static methods
- move newly-`internal` methods together in `DefaultHtmlGenerator`
- correct placement of `DefaultHtmlGenerator.GetValidationAttributes()` comment
Reacted to options and hosting changes after rebase.
Add extensions for TagHelperOutput to copy and merge from TagBuilder.

- Added tests to validate functionality of all TagHelperOutputExtension methods.

#1319
Add FormTagHelper.

- Added the FormTagHelper.
- Utilized the IHtmlGenerator to share base functionality with the HTMLHelper counterparts.
- Added tests to validate FormTagHelper functionality.

#1246