[Orxonox-commit 1819] Keybindings merging

[Reto Grieder]

Hi devs,

Hopefully for the very last time:
*** DELETE YOUR KEYBINDINGS.INI FILE ***

Because from now on, orxonox will always merge the file in 
data/defaultConfig with the one in build/config if you are running the 
game from the build directory.
Installed runs will not be affected by this change.

Also note that writing "NoBinding" into the file in build/config will 
overwrite the binding in data/defaultConfig with an empty string!
But the Keybinder already takes care of that when changing keybindings 
from the console or menu.

cheers,
Reto