- [ardrone] added daren's mag freeze fix
 - [ardrone] daren's mag freeze fix, cleaned up acc. to suggestions
Merge branch 'master' of https://github.com/paparazzi/paparazzi into ardrone_mag_freeze
Merge pull request #767 from x75/ardrone_mag_freeze

[ardrone] added daren's mag freeze fix
[ardrone] use gpio API instead of system call
[mission] add support of rotorcraft to the  mission control module
[invariant] invariant filter less verbose by default
Merge branch 'master' of https://github.com/paparazzi/paparazzi into x75

Conflicts:
	sw/airborne/boards/ardrone/navdata.c
 - pre summer fiddlings: mag freeze, imu startup