Implemented subscribe() in r4j in order to simplify my code
Implemented CanvasPaint example. Requires even more modifications and fixes to reactive4java :)
Added patch for my reactive4java changes to support these examples
Normally I'd put images in a resource folder, but this will do
Every time you do mouse move you generally want drags as well, so moved that into FromEvent
Refactored out FakeCanvas and FakeEvent.detectMouseDownOn for use in crop