remove proxying of images via canvas

see http://jsperf.com/canvas-drawimage-vs-image-drawimage
fix loading of remote resources mentioned >once
Merge pull request #210 from Animatron/play-508-duplicated-images

fixed PLAY-508
fix subject_id being not random enough

computers are now fast and can do two function calls in one getTime,
this should fix it.
fix autostart
fix volume adjustment when WebAudio is available
Merge pull request #211 from Animatron/play-496-volume-fix

fix volume adjustment when WebAudio is available
add exception check when creating AudioContext
Merge pull request #212 from Animatron/play-513

add exception check when creating AudioContext
move trigger after notifying loader of success
Merge pull request #213 from Animatron/play-501

move trigger after notifying loader of success
Merge branch 'master' into api-refactoring

Conflicts:
	src/module/audio.js