Added MythGame and MythArchive support.
All code was provided by Britney Fransen (LinHES).

Tweaked the mythburn window in mythburn-ui.xml and also
the exportnative window in mythnative-ui.xml.

new file:   game-ui.xml
new file:   mytharchive-ui.xml
new file:   mythburn-ui.xml
new file:   mythnative-ui.xml