[conf] sort conf example and test
[optitrack] Give feedback about following drones and fix gps
[conf] stm32-upload: only verify for dfu-util >= 0.7
Merge pull request #718 from fvantienen/optitrack_fix

[optitrack] Give feedback about following drones and fix gps
[subsystem] possibility to poweron gps and imu via gpio at init

closes #706
[airborne] check ned_initialized_f in stateIsLocalCoordinateValid
[ins] alt_float: properly reset_alt_ref if !USE_BAROMETER
[ins] ins_int: INS_SONAR_MIN_RANGE defaults to 1mm
Merge branch 'master' of https://github.com/paparazzi/paparazzi into delflyDesperado