Upgraded C# Wrapper for Usergrid

Hi guys,

I stared using the C# sdk for Usergrid and it was lacking a lot.
I upgraded it completely.

I'm aware not all Model are complete, but I made some lot's of upgrades.
Plus, I made it to a Portable Library, which means it can be consumed by almost any .NET app. (.net 4, 4.5, win8 apps & windows phone 7/8).

Check it out. let me know what you think.