Added Call to Action to first slide

Configurable in options.
To use, set `call_to_action` to true which is also the default.
Customize text by setting `call_to_action_text` in options. Default text is in language file `start`
Attributed touchpad pinch source
Tweaks to Firefox media rendering
CSS Cleanup
Call to action styles
Fix for loading message sticking around on YouTube videos
Tweaked call to action text
Cleanup
Latest Compile