Returns the current rotation of the device around it's Z-Axis in 90 degree steps.
		
		app.GetRotation() → number: angle in degrees (0..360): 0 or 90 or 180 or 270
		
		The values are relative to the initial orientation of the device on startup.
		
		See Also: GetOrientation
		
			Example - Repeatedly Show Rotation
			
				function OnStart()
				{
				    app.Animate( ShowRotation, 2 );
				}
				
				function ShowRotation()
				{
				    var mode = app.GetRotation();
				    app.ShowPopup( mode );
				}
			
			
		 
		
			Example - Show Rotation and switch Orientation
			
				cfg.Portrait;
				
				function OnStart()
				{
				    app.Animate( ShowRotation, 2 );
				    setTimeout( 'app.SetOrientation("landscape")', 5000 );
				}
				
				function ShowRotation()
				{
				    var mode = app.GetRotation();
				    app.ShowPopup( mode );
				}