Moved all GamePad code to Input folder.
Added common GamePad class.
Added vibration support to GamePad under XInput.
Fixed web platform to support platform partial methods.
Added copyright header.
Fixed WinPhone platform to support platform partial methods.
Fixed Android platform to support platform partial methods.
Fixed Ouya platform to support platform partial methods.
Fixed PSM platform to support platform partial methods.
Fixed iOS platform to support platform partial methods.
Renamed GamePadState.InitializedState to Default.