Animation will stop playing when documents are switched.
Animation will stop playing when node is selected on stage.
Animation will stop playing on publishing.
Animation will stop playing when timeline is switched, edited, duplicated, created and duration changed.
Merge pull request #575 from NickyWeber/bugfix/#451_more_playback_stop_events

Bugfix/#451 more playback stop events
Merge pull request #576 from cocojoe/develop

Preview thumbnail fix