Removed "touchstart" to prevent Android issues

Removed "touchstart" event in order to overcome some android 4.1-4.3
issues (samsung devices) where the click on the bigPlay area fired two
events. The player started playing and immediatly paused again. I don't
know if that will have any side effects. I testet various mobile devices
sucessfully.
Added comment with change explanation
Merge pull request #1212 from MoritzGiessmann/master

Removed "touchstart" to prevent Android issues