[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.
[modules] gps_ubx_ucenter, extra flag PRINT_DEBUG_GPS_UBX_UCENTER

which should only be used on platforms with printf support (e.g. linux on AR Drone) or when using semi-hosting
[doc] Two simples updates int the documentation of the project.

Recompiled the paparazzi algebra documentation to include the refs to the images in the file.

Updated the link to the wiki in the readme of the controle loop documentation.

closes #668
[export] fix datalink export (missing file)
[MF_DAQ] update and fix mf_daq module

- use telemetry message
- fix datalink event
- protection for memcpy max size
[gcs] fix AGL display in edit waypoint box

also fix a strange bug where set_adjustment function doesn't correctly
display the actual initial value (but it was correctly set, only display
was 0.)
[sonar] sonar system using ABI interface

- unified interface for sonar (sonar_adc was broken with latest commit
  for ardrone)
- median filter removed from ins_int, implement in sonar drivers if
  needed
- compiles but not tested yet
[ins] remove obsolete ins update functions on baro and sonar
[sonar] fix some sonar related issues