[imu] enable sign/sens defaults for aspirin_v2.2 as well
[AOA] some cleaning of the angle of attack module
[gps] fix skytraq binary parser: correct scaling and signed values, thx for reporting Gerard
while here clean up a little
hopefully finally closes #167
[airframes] update imu/ahrs freq conf for aspirin in microjet lisa/m example
[electrical] fix missing defined
[tests] fix test_baro for lisa
[sw/ext] update libopencm3 to latest master
[sw/ext] only build stm32 targets of libopencm3
[stm32] update can for latest libopencm3
[conf] pass configured AHRS_x_FREQUENCY on for rotorcrafts as well
[sim] fix symbolic link
[log/replay] this should allow to replay logs including procedures

fix #227
adjusted scaling of ezcurrent sensor
[modules] minor cleanup of ezcurrent sensor
[gps] update doxygen comment
[peripherals] adxl345_spi: set in/out length to fixed 7 again, mixed lenght not working reliably
[rotorcraft] print info if using FAILSAFE_GROUND_DETECT
[peripherals] hmc58xx: fix typo in comment and make explict separate defines for Y,Z data regs for HMC5843/HMC5883
[stm32][spi] select slave after configuring clock/phase, etc of peripheral
Also:
- replace tx_length_case by simpler use_dummy_tx_buf
- minor comment cleanup while here...
[imu] correct mag axes for aspirin_v1.5. RECALIBRATE!!!