Implements #14: support for gesture commands
Implemented as additional unnamed hotkeys. Defined in gestures section of configuration file. Supported gestures are: four finger swipe up/down right/left; four finger pinch/spread; three finger single/double tap; two finger double tap. (The MM client app handles two finger pinch/spread differently, as ZOOM.)
I find the four finger gestures impractical on the small screen of an iPhone.