magnetometer/gyro calibration tests
convert to Eigen
better method, but man, my offsets are awful

gotta move the sensor, i think
trying to do tilt compensation, probably wrong
temperature-calibrated gyro input
kalman filter for bias estimation; still buggy
this kalman filter doesn't work at all

there's a much simpler way to do this, coming next
http://www.freescale.com/files/sensors/doc/app_note/AN4246.pdf
this least-squares solution works much better

however, correlated inputs mess it up; maybe we can de-weight each
sample based on informativeness (like, 1-dot product)
weight calibration samples by cosine distance from previous
Added online calibration and reorganized some stuff
vis: read new log format
more indicators
begin design of enclosure for all hardware

just roughing out dimensions here relative to battery holder widget
roughing in an rpi
bosses with gussets
more accurate rpi
better mounting thingies
manufacturability tweaks