multirotor_att_control: use PID lib for yaw rate control
multirotor_att_control: style fixes, cleanup
Hotfix: forbid integrator to accumulate NaN values if they ever would occur
Hotfix: Fix integrator parameters
Integral fixes, last parts
Startup scripts: Corrected cases where commander was not started, updated several outdated scripts
Startup scripts: Start the commander early and let it try to open the mavlink_fd with 20Hz
Merge pull request #515 from julianoes/startup_fixes

Startup script update
remove commander from hil startup scripts
Merge pull request #517 from thomasgubler/hil_startupscripts

remove commander from hil startup scripts
Startup scripts: fixed stupid typo
Merge pull request #518 from PX4/hotfix_fixedwing_startup

Startup scripts: fixed stupid typo
Hotfix: Be more aggressive about SPI2 init on v1 boards
multirotor_pos_control: failsafe against invalid yaw setpoint in AUTO
missionlib: Added geo.h include, without this the _wrap_pi function returned garbage (e.g. for the yaw setpoint in auto)
Merge pull request #522 from PX4/hotfix_yaw_auto_bug

missionlib: Added geo.h include,
Merge branch 'master' into yaw_pid_fix
Don't limit the PWM output maximum for the IRIS to use the whole thrust range
fix MEAS airspeed and airspeed calibration
Merge pull request #525 from thomasgubler/airspeed_meas_calibration

fix MEAS airspeed and airspeed calibration