Add an empty scenario to the controller

The empty scenario is needed if we want the controller to do nothing.
(Motivated by #129).
Add a script generating a config file for the LINC

The `config_gen` script allows to provide interfaces that should be bound
to a logical switch and the output file to which the config should be written.
(Motivated by #129).
Merge remote-tracking branch 'origin/master' into issue129

Conflicts:
	scripts/of_controller_v4.erl