Updated to Surface SDK 2.0

essentially:
contactTarget = new ContactTarget(IntPtr.Zero,EventThreadChoice.OnCurrentThread,true);
became
touchTarget = new TouchTarget(IntPtr.Zero,EventThreadChoice.OnCurrentThread,true);

position and size values are now normalized using:
ScreenWidth = InteractiveSurface.PrimarySurfaceDevice.Width;
ScreenHeight = InteractiveSurface.PrimarySurfaceDevice.Height;

+ some minor changes

only tested with input-simulator for now.

Renamed help-patch according to version update
Updated links in README.txt to Surface SDK 2.0