Remove the JSON.NET NuGet package

Until JSON.NET supports the Monotouch and Monodroid profiles, we need to
reference JSON.NET from the ext folder.
Remove Microsoft.Bcl.* build targets

According to paul, Microsoft.Bcl.* is no longer needed in RxUI 5
Remove the Microsoft.Bcl.* packages

According to paul, these are no longer needed for RxUI 5.0
Remove Microsoft.Bcl.* from packages.config

These packages should not be referenced any longer.
Remove this source control bindings bullshit

It's Git's world y'all!
Add project configuration sections to WP8 projs

These projects seemed to be missing the various configuration sections
which prevented them from building properly. I compared these projects
to a vanilla Windows Phone Class Library project and added in the
missing sections and now the WP8 projects build.