Update Web API product versions

Isolate `MediaTypeFormatterTests.MaxCollectionKeySize_RoundTrips`

- in recent CI run, another test failed because `MediaTypeFormatter.MaxHttpCollectionKeys == 1` temporarily
- also left `MediaTypeFormatter.MaxHttpCollectionKeys == 125` which could affect later tests

ElementalValueProvider performs incorrect ContainsPrefix check.

Add `ModelMetadata.HtmlEncode` property

- use new `ModelMetadata.HtmlEncode` property in HTML helpers
 - conditionally in default HTML display and editor object templates (e.g.
   `@Html.DisplayFor()`) when value is non-null and the template is invoked
   with template depth greater than 1
 - unconditionally in `@Html.DisplayText()` and `@Html.DisplayTextFor()`

Add `ModelMetadata.HtmlEncode` property

- use new `ModelMetadata.HtmlEncode` property in HTML helpers
 - conditionally in default HTML display and editor object templates (e.g.
   `@Html.DisplayFor()`) when value is non-null and the template is invoked
   with template depth greater than 1
 - unconditionally in `@Html.DisplayText()` and `@Html.DisplayTextFor()`
- test new property and its use

Also test `DisplayTextExtensions`
- unit test gap

Remove reference to non-existent test file

Upgrade ODataLib version from 6.7.0 to 6.8.0

Here's the annuncement of ODataLib 6.8.0 release:

http://blogs.msdn.com/b/odatateam/archive/2014/09/28/announcement-odatalib-6-8-0-release.aspx

Microsoft.AspNet.Facebook 1.1.0 Beta

Update Microsoft.AspNet.Facebook version.

- Due to the CannotCreateCookies hook feature the version is upping to 1.1.0.

Updated the assembly version numbers to 5.2.2.0