Port expander driver first hacky version
Updated AR.Drone parameters

Flight tested May 7th, 2014.
Increase UART1 & UART5 RX&Tx buffer sizes

To fix MAVLink message garbling problems.
Merge pull request #991 from Kynos/master

Updated AR.Drone parameters
Merge pull request #1009 from PX4/inav_fix

position_estimator_inav: stability fix
Merge branch 'master' of github.com:PX4/Firmware into pca8574
PCA8574 driver: Cleanup, ready for final testing and production
Enable the driver as default for boards having it
PCA cleanup: Full interfaces ready for AP use
Merge pull request #1024 from PX4/pca8574

PCA port expander
Minor fixes to MAVLink
position_estimator_inav: GPS delay compensation
Merge pull request #1026 from PX4/mavlink_fixes

Minor fixes to MAVLink
position_estimator_inav: add buffer for rotation matrix to do accel bias correction properly
ubx driver: fix unit of speed and position accuracy estimate
Merge pull request #1029 from PX4/ubxaccuracyunit

ubx driver: fix unit of speed and position accuracy estimate
position_estimator_inav: default GPS delay changed to 0.2s
ubx: disable all debug messages
ubx: send update only if got POSLLH & VELNED & TIMEUTC
Merge branch 'ubx_no_debug' into inav_gps_delay