[X2Go-Dev] Bug#74: make nxagent keybindings configurable

[Alexander Wuerstlein]

Package: nxagent

The hardcoded default nxagent keybindings (e.g. Ctrl-Alt-t opens a terminal in
Gnome or closes a nx/x2go session) collide with several more or less popular
window managers or desktop environments. Since any hardcoded configuration will
inevitably collide with some other configuration somewhere, the only sane way
out of this is making the keybindings configurable, which the attached patch does.