first pass at adding plex
Merge branch 'master' into app-plex
fix make update
improve build speed, RAM+CPU MOAR
improve reboot and gracefully handle media removal,

 - fixes #25, #13
fix handling of OSX builds
improve support for remote torrent adder
ssh-key works again
fix plex startup
disable /etc/ persistence, refs #26
plex starts on boot
change spash image, refs #20
add version to rootfs
improve drive init
avoid unneeded rebuilds on usb creation
fix plex startup
add more dirs to sync