Better way to hide the loading modal.

I think it makes way more sense to put this code in app.js rather than
the subtitles controller.
Refactored languageChanged()

We were always calling it without a version number, so remove that
parameter.

Generally cleaned up the function.
Use opensans font in the title/description metadata textareas
Fixing icon position, it will now follow info tray to a given buffer.
Merge pull request #786 from pculture/editor-fixes

Editor fixes