Drawing while pen move

[fu11zero]

Use wacom (or other drawing device) movement as toggle drawing hotkey.

Right now I am using mouse and wacom tablet at the same time. So, it would be nice if the pen could just and only draw, erase, clean without any keyboard hotkeys. Just pen buttons and movement. And mouse should do the mouse stuff for pointing and pressing ui-buttons.

Toggling should behaive as described in issue "toggle active on hotkey down, deactivate on hotkey up #58".

I suppose, it is not difficult to implement to allow bind like this:

# Toggle drawing ON on start moving stylus 
# and toggle drawing OFF on stop moving stylus 
HOTKEY="Wacom Bamboo1 Pen stylus"

I do not know if there is a api to detect start and stop stylus movement, but gnome-control-center in "Wacom Tablet" menu highlights pen when it moves, and dims when it is not.