[conf] fix type in control_panel example
[fms] Fix compiler warning for network_write
[ardrone2] Implemented sonar
[gps] Add a new GPS based on the datalink
[ground_segment] Add Optitrack to Ivy service
[gps] GPS datalink update to newest master.
[ins] Added the possibility to use GPS for altitude estimation
[ardrone2] Fix baro measurement spikes