[airborne] some minor style fixes
[fixedwing] rename LOW_BATTERY_KILL_DELAY to CATASTROPHIC_BAT_KILL_DELAY
[tmtc] gpsd2ivy: commandline options and verbose mode

- fix nan checks and warnings
- default to broadcast instead of multicast on linux
- make ivy_bus, gpsd server and port configurable via commandline
- added verbose mode which should help to track down issue #658
[mcu_periph] sys_time: get_sys_time_msec and cleanup
[omap] Fix GPIO warnings
[vff] Disable debugging by default
[ardrone2] Fix AHRS propagate frequency
[ins] INS_PROPAGATE_FREQUENCY defaults to AHRS_PROPAGATE_FREQUENCY if defined
[conf] cleanup INS_ and AHRS_PROPAGATE_FREQUENCY
[rotorcraft] guidance_h_ref: dynacmically adjustable max_speed

- set_max_speed via settings

closes #664
[conf] hff and geomag for quadrotor_lisa_mx.xml
[rotorcraft] count motor_mixing saturation cases

and send them in ROTORCRAFT_STATUS motor_nb_error.
One combined lower and upper saturation (nb_failer) counts 10 times as much.