Add new main menu layout called MythQ

This adds a new experimental screen layout similar to the SkyQ interface.

You can change to it by going into the Theme settings and make sure Use MythQ menu layout is checked.

In the screenshots the picture on the left is actually the live video of the active media player that can come from any video source like live TV, video file, webcam, IPTV etc.

Example 1 of the new MythQ screen layout. Example 2 of the new MythQ screen layout. Example 3 of the new MythQ screen layout.