Re-design

New Features:

• Converted to Portable Class Library
• Removed RestSharp in favor of HttpClient
• All calls are async
• Support for .NET 4.0, .NET 4.5, Silverlight 5, Windows Phone Silverlight 8, Windows Phone 8.1, Windows Store 8 (Profile136)
• Support Enforce Signed Header

-Converted to Portable Class Library
-Removed RestSharp in favor of HttpClient
-All calls are async
-Support for .NET 4.0.3, .NET 4.5, Silverlight 5, WP8, Windows Store 8