Recognizer: Add option to use buttons to toggle gesture drawing
Recognizer: Add option to use buttons to toggle gesture drawing

Add new lager_recognizer command-line argument, "--use_buttons".

When this is entered, gestures will only be recognized while one of
the sensor buttons is pressed.

If the argument is not entered, the recognizer works as before
(recognition enabled at all times).

Minor refactoring.

andresodio/lager,andresodio/lager,andresodio/lager,andresodio/lager