Trigger ready after toggle to make android 2.x start playing video

Affects at least issues #32 and #275
Custom load event for android devices
Apply method to proof context
Hide video tag for Android version < 3
Fix Android firefox support
Disable android tweaks for Opera
Prefer mp4 source
Merge pull request #335 from flowplayer/bug/android

Trigger ready after toggle to make android 2.x start playing video