Block UI during click animations

Signed-off-by: Michalis Vitos <info@michalisvitos.gr>
Merge branch 'BlockUI' of github.com:ExCiteS/Sapelli + re-added selective blocking (not currently used)

Conflicts:
	CollectorAndroid/src/uk/ac/ucl/excites/sapelli/collector/activities/CollectorActivity.java

Signed-off-by: Matthias Stevens <matthias.stevens@gmail.com>