Add setting to turn "autoplay" on/off for youtube/vimeo links.

* Also attempt to avoid auto playing multiple videos when auto opened from self post
Pause on collapse of comment (or of any parent comment)
Support youtube timestamps to be passed directly as ints
style tweaks "if (" vs "if("
Merge pull request #885 from thybag/feature/autoplay-controls

Add setting to turn "autoplay" on/off for youtube/vimeo links.