Implemented the double-click gesture and removed some old gesture code.
Added InputManager::CreateAndGetDevice.
Fixed devices being assigned wrong IDs.
Implemented the hold-to-trigger gesture.
Implemented tap gesture.
Implemented pinch gesture.
Removed some accidentally left in debug code.
Implemented multi-touch rotate gesture.
Added some documentation.
Added a common gesture interface, some more documentation.
Removed some redundant code; fixed some warnings.
Some minor fixes, some more documentation.