Use an elm Slider instead of the custom slider group
Some theme work on the mediaplayer
Revert the usage of elm Slider

Back to a custom slider edje group, elm Slider take the focus when dragged with the mouse, making the whole app focus unusable.
Redone the new slider with the elm dark theme.
Initial commit for the new '2-level' mainmenu

* theme still need work
* updated all the modules icons
* modules need to be updated to use the second level
Use the mainmenu second level in Music and Movie activities

* some initial work on subitems theme
* updated the compiled edje theme
* Music: disabled library rescan on activity startup