First pass at adding regkeys for opening .mgcb files in the Pipeline tool from Visual Studio.
Added macros for VS and regular file associations.
Added file system association for Pipeline tool.
Add the current EXE path to the search paths for MGCB.
Merge pull request #3183 from SickheadGames/vspipe

VisualStudio Support for Pipeline GUI Tool
Upgrade Android to OpenTK-1

Also added Property to Activity to control if the rendering is done on
the UI thread or not. By not rendering on the UI thread we save
a SyncContext.Send call in the underlying AndroidGameView.
This can introduce up to a 100ms delay in a Render call which
can cause a stutter.

By default we will leave RenderOnUIThread = true to maintain
backwards compatability.

The upgrade to OpenTK-1 was required as the fix for this
is not present in the OpenTK 0.9.9.3 version as it is there
for backwards compatabiltiy only.
Merge pull request #3185 from dellis1972/androidrenderthread

Upgrade Android to OpenTK-1