Wemo API toggle and hold-until-lock features

Extend lock script to toggle lock based on current state of
wemo light. Before, it used an os.system() call, which was slower.

Also, let the user hold down button for 0.5 seconds. At that point, the
door lock toggles. Before, user had to release button before the door locked.
Merge pull request #1 from Slix/master

Wemo API toggle and hold-until-locked features