Converted all base_buttons to use area rather than position.
Removed base_small_button, base_medium_button and base_wide_button.

	modified:   base.xml
	modified:   browser-ui.xml
	modified:   config-ui.xml
	modified:   controls-ui.xml
	modified:   gallery-ui.xml
	modified:   game-ui.xml
	modified:   music-ui.xml
	modified:   musicsettings-ui.xml
	modified:   mytharchive-ui.xml
	modified:   mythburn-ui.xml
	modified:   mythnative-ui.xml
	modified:   netvision-ui.xml
	modified:   news-ui.xml
	modified:   recordings-ui.xml
	modified:   schedule-ui.xml
	modified:   settings-ui.xml
	modified:   stream-ui.xml
	modified:   video-ui.xml
	modified:   weather-ui.xml
	modified:   welcome-ui.xml