Porting CheckBox and CheckBoxFor unit tests

Partial fix to #453
Fix for #291 : Reacting to addition of Base64UrlDecode and Base64UrlEncode in webUtilities.
Replacing ViewResultBase with ViewExecutor
Mvc should not pull in the K.Roslyn package
Fixes #1427
Issue #220 - Flags enum does not bind
Fix - After TypeConverter support this works. Adding tests for the same.
Merge remote-tracking branch 'origin/release' into dev
Revert "Mvc should not pull in the K.Roslyn package"

This reverts commit 6050d73554a3da731ece506eba654dc3a8b07972.
Fix pdb generation for win7/coreclr
Merge branch 'release' into dev
React to KRuntime change
Merge branch 'release' into dev
Adding functional tests to verify round tripping of names generated by
HtmlHelpers
CompositeValueProvider.GetKeysFromPrefixAsync throws null if provider is not an
IEnumerableValueProvider

Fixes #1419
Refactoring the ControllerActionDescriptorProvider
Fix for #996 - ViewComponentInvoker should get TypeActivator from DI.
Rename GlobalModel -> ApplicationModel

This also comes with a rename of the namespace
Microsoft.AspNet.Mvc.ApplicationModel to
Microsoft.AspNet.Mvc.ApplicationModels.

Also tuned up some parameter and variable names for increased
understandability.
Reacting to System.Collections.Concurrent versioning change
Changing NewtonSoft.Json version to 6.0.6
Change TagBuilder Attributes and HTML Helper dependencies to be case insensitive.

- This involved adding the StringComparer.OrdinalIgnoreCase comparer to the TagBuilder's Attributes dictionary.
- Added tests to validate that all methods that made use of TagBuilder.Attributes abide by the new ignore case mechanic.
- Added two sets of tests to validate the new functionality of Object => Dictionary HTML helper tests.
- Modified a functional test that utilizes HTML Helpers to provide same attribute-different case objects.
- Fixed existing HTML helper tests to account for new ordering of attrbutes (dictionary no longer adds key value pairs, it sets them).

#1328
React to case insensitive TagHelperOutput.Attributes.

- Cleaned up some existing bad code that worked around case sensitive TagHelperOutput.Attributes.
- Modified MergeAttributes to be case insensitive when it comes to merging class attributes.
- Added a test to verify the new MergeAttribute case insensitive class merging.

aspnet/Razor#186