Added Auto Grab for Key-Bindings specified in configuration file.

Added automatic grabbing of key-bindings, which are specified in the
configuration file. These key-bindings cannot be used by any other
application and are reserved for AirWM.

Signed-off-by: Martin Jorn Rogalla <martin@martinrogalla.com>
Merge pull request #24 from AirWM/AutoGrabKeyBindings

Added Auto Grab for Key-Bindings specified in configuration file.