Fix #620, Remove legacy / non-unobtrusive client side validation
- remove `ViewContext.UnobtrusiveJavaScriptEnabled` property and all references
- avoid `ViewContext.GetFormContextForClientValidation()` calls since
  ternary expression is more explicit and we were inconsistent
- improve `ValidationMessage()` comments
- don't treat `ModelState.IsValid` as if it were still nullable
Cleanup unused `FormContext` members due to legacy validation removal
- provide new property back for customer use
- remove unused FieldValidationMetadataClass
1. Introducing XML Input Formatters.
2. Adding DelegatingStream class
3. Unit + Functional tests for formatters.
Add friendly name to action descriptor. Issue 820

Used in error messages for various attribute routing pieces, and anywhere
that you need a display name for an AD.
Add friendly name to action descriptor. Issue 820

Used in error messages for various attribute routing pieces, and anywhere
that you need a display name for an AD.
Adding parameter replacement
Reacting to Roslyn package changes
Adding support for content negotiation.
This change consists of :
1. Conneg based on request headers, supports the following 3 scenarios:
	a. ContentType property on ObjectResult set to null or is empty.
	b. ContentType property on ObjectResult set to a single content type.
	c. ContentType property on ObjectResult set to multiple content types.

2. Parsing Helpers, comparers and extensions for comparing various http headers.
3. Tests.

Open workitems:
1. Remodel JsonResult and ContentResult to be a derivation of ObjectResult.
2. Populate DeclaredType.

Conflicts:
	src/Microsoft.AspNet.Mvc.Core/Formatters/OutputFormatterDescriptor.cs
	src/Microsoft.AspNet.Mvc.Core/Microsoft.AspNet.Mvc.Core.kproj
	src/Microsoft.AspNet.Mvc.Core/OptionDescriptors/OutputFormatterDescriptorExtensions.cs
	src/Microsoft.AspNet.Mvc.Core/Properties/Resources.Designer.cs
	src/Microsoft.AspNet.Mvc.Core/Resources.resx
	src/Microsoft.AspNet.Mvc.HeaderValueAbstractions/MediaTypeHeaderValue.cs
	src/Microsoft.AspNet.Mvc.HeaderValueAbstractions/MediaTypeWithQualityHeaderValue.cs
	src/Microsoft.AspNet.Mvc/MvcOptionsSetup.cs
	src/Microsoft.AspNet.Mvc/MvcServices.cs
	test/Microsoft.AspNet.Mvc.Core.Test/Microsoft.AspNet.Mvc.Core.Test.kproj
	test/Microsoft.AspNet.Mvc.Core.Test/OptionDescriptors/OutputFormatterDescriptorExtensionTest.cs
	test/Microsoft.AspNet.Mvc.HeaderValueAbstractions.Test/MediaTypeHeaderValueParsingTests.cs
	test/Microsoft.AspNet.Mvc.Test/MvcOptionSetupTest.cs
Moving to the latest pattern of Specifying formatters using options
Responding to comments
Updating System.Xml.ReaderWriter to 4.0.10.0
Removing a stale proj reference in .sln
Fix Stylecop failure
- long line
Improve `HtmlHelper` extension points
- address all of #659 and a bit of #874 (avoid `public virtual` methods in
  `HtmlHelper`)

- make `MetadataProvider` and `GetClientValidationRules()` `public` and
  therefore available to extension methods
- remove unused `GetValidationAttributes()` overload
- make remaining `GetValidationAttributes()` overload (and not
  `GetClientValidationRules()`) `virtual`, allowing derived classes to
  change the attributes without overriding all callers
- reverse `GetValidationAttributes()` and `GetClientValidationRules()`
  parameter order to match precedence
- add `GenerateName()` and `GenerateValidationSummary()` to make
  `protected virtual` method names consistent
- `Name()`, `ValidationSummary()` and `TextArea()` are no longer `virtual`
  because `protected virtual Generate*()` methods exist for all
Make longest `@Html.DisplayForModel()` overload an extension method
- consistent with @Html.EditorForModel()` overloads
Return a copy of the route values in functional tests.

This is a workaround for a Json.Net + CoreCLR issue.
Changing GetLibraryExport to GetAllExports
Adding TextPlainFormatter to always handle returning strings as text\plain format.

Conflicts:
	src/Microsoft.AspNet.Mvc.Common/Encodings.cs
	src/Microsoft.AspNet.Mvc.Core/Formatters/JsonOutputFormatter.cs
	src/Microsoft.AspNet.Mvc/MvcOptionsSetup.cs
	test/Microsoft.AspNet.Mvc.Core.Test/ActionResults/ObjectContentResultTests.cs
	test/Microsoft.AspNet.Mvc.Test/MvcOptionSetupTest.cs
Stylecop fixes
Added Logging to Mvc