driver for the TeraRangerOne I2C ranger finder
update attitude_estimator_ekf, includes matlab

This adds the latest c implementation (matlab coder) of
attitude_estimator_ekf, the .m matlab script and the .prj file with the
settings to export the matlab code to c
Merge remote-tracking branch 'upstream/master' into attitudeekf
att ekf: add param to enable/disable J
att ekf: add descriptions for params
Merge remote-tracking branch 'upstream/master' into attitudeekf
Merge remote-tracking branch 'upstream/master' into attitudeekf
Merge remote-tracking branch 'upstream/master' into attitudeekf
update attitude estimator ekf to latest version

mainly saves stack size
mavlink: use altitude AMSL in VFR message
added px4flow integral frame, adjusted px4flow i2c driver, adjusted postition_estimator_inav
Fixed formatting of flow driver
Merged master
Formatting fixes
More formatting and cast fixes
More formatting fixes
Scan both buses
Kill last usleep()
deleted last PX4FLOW_BUS to enable scan on both buses
scan also 3rd available bus