Draft work on WinRT port.

Code compiles, I make no other promises right now.
Fix to previous check (jsonserializer bug)

Previous check-in for WinRT port had some bugs in one of the
jsonserializer methods for creating collections. Now fixed.
ListTweetsOnHomeTimeline tested and working in WinRT app and also in
.Net 4.0 console app.
Fix incorrect cpu setting on main tweetsharp project in debug build

Stopped tests running correctly and geneated compiler warning about
mismatched architecture.
Build and pack for nuget

Build release versions of all assemblies assemblies and update nuget
package.
Fixes and updates for WinRT library

Debugged basic usage of WinRT library in universal project on both phone
and non-phone project.
Changed nuget package so json.net is 5.0.8 for WP7x projects and 6.0.3
for all others.
Test updated nuget package installed into projects on various platforms.
Fixed any issues.
Build updated Hammock nuget package.
Commit embedded hammock changes.
Async/Await Support Draft

Implement Async/Await support for WinRT with new compiler directive for
platform support. Should now create a .Net 4.5 project that also
implements Async/Await support. Not planning to add this to older
platforms as not everyone may want to take on the additional bcl
dependencies. Existing code won't use it, and new projects should be on
new platforms (if not, they can implement a wrapper themselves using
taskcompletionsource and the delegate based methods).
Add Net45 Support, Use T4 for Async/Await

Fixed changes from yesterday to use the T4 templating engine for
creating the async/await methods.

Added a Net45 assembly with async/await support.

Renamed async/await methods to end with Async as is the common pattern.