Add an option for debug output

[ohthehugemanatee]

I'm trying to use gebaar on my wacom touchscreen, but when I run it... no console output. Other comparable projects offer a debug-to-stdout option, or debug logging, or similar. Anything to validate that we are actually receiving events from libinput, and perhaps help work out if/why they are identified as gestures.

[Frenzie]

You can see what libinput does with (sudo) libinput debug-events.

[ohthehugemanatee]

yes, libinput sees everything. It's only gebaar that doesn't respond with anything. Plus, gebaar is the only system (that I know of) that doesn't use the output of debug-events.... So I want to make sure the connection to libinput is working.