Fix red: Invert buttons in RTL mode

- Revert renaming of button_set_flip()
- Moved rtl flipping logic to apps/actions.c as a static function
- Joined rtl_button_flip_needed() and button_flip_horizontally()


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22962 a1c6a512-1295-4272-9138-f99709370657
6 files changed