Replace run button with green flag and stop sign

Fixes #146.
Replaced mouseover with mouseenter listeners

Only needed upon entry and was wasteful to use mouseover.
Images are pre-loaded

Fixes #129.
Close buttons no longer auto hide

And they are place along with the new green flag and stop sign.
Improved layout of backside buttons
Backsides have minimum dimensions
Major redesign of backsides

Removed settings button. Backside shows most common settings and can
toggle whether showing more advanced settings.
Stopped using before pseudo element

Since it doesn't reliably support Unicode or HTML markup.
Updated compiled version
Merge pull request #151 from ToonTalk/master

Updating gh-pages to master