idea: onClick execute condition adjustable (not much effort)

[IsiTapier]

It would be quite usefull to have to possibilty to disable the execution of the onClick function on first touch / last touch (JoystickView.java line 451 and 467) I had the issue that this behaviour led to a double execution on touch start / end which crashed my http connection, which couldn't handle these close executions. Please just add a function to disable these 2 extra executions if needed.