Implement shutdown/reboot start/stop services etc

new features:
shutdown/reboot your raspberry
start/stop services
mount/unmount partitions

Only availables if www-data has root permission

Also fix api login. always returned login failed

Some images

http://i853.photobucket.com/albums/ab94/lorenzorogai/warning_zps12d32a82.png

http://i853.photobucket.com/albums/ab94/lorenzorogai/mountpoint_zpsa41eacfe.png

http://i853.photobucket.com/albums/ab94/lorenzorogai/nopermission_zpsb9c58743.png

http://i853.photobucket.com/albums/ab94/lorenzorogai/nopermission-services_zpsf3922b33.png

http://i853.photobucket.com/albums/ab94/lorenzorogai/nopermission-disks_zps1424cd23.png