#473 Gallery Edit Photo Effect

I stucked at verifying effect is applied and photo is changed. It seems
that this part is using canvas to chaging the effects.
Anyone got some idea about this? Attached is the code.
#473 change sleep to wait for condition

Change time.sleep to wait_for_condition
Merge branch 'issue_473'

Conflicts:
	gaiatest/tests/gallery/manifest.ini
Merge remote-tracking branch 'upstream/master'