TODOs for Theme manager:
* style cleanup (-> Haiku style)
* make ParseMessage more robust
* forbid quitting while themes are loading!
* ideas for addons:
	- ~/config/settings/Tracker/DefaultFolderTemplate/ (default background ??)
	- dircolors (cf. http://linux.die.net/man/5/dir_colors )
	- icons (/etc/icons ? svg/hvif, setmime...)
	- mouse cursors (needs app_server fixes ??)