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
Start TELEM2 MAVLink instance with 230400 baud
Merge remote-tracking branch 'upstream/master' into attitudeekf
Merge branch 'master' of github.com:PX4/Firmware into indoor
Merge remote-tracking branch 'upstream/master' into attitudeekf
update attitude estimator ekf to latest version

mainly saves stack size
Enable TELEM2 MAVLink, forward local pos at 30 Hz if connected via USB
Merge branch 'master' of github.com:PX4/Firmware into indoor
Merge branch 'master' of github.com:PX4/Firmware into indoor
Obey vision estimates in attitude estimator if available
Merged master
Merge branch 'master' of github.com:PX4/Firmware into indoor
Start the laser on a port not offending the 2nd MAVLink instance
Start flow driver, start MAVLink instance with right arguments
Merge branch 'master' of github.com:PX4/Firmware into indoor
Merge branch 'master' of github.com:PX4/Firmware into indoor