adds initial outline for IMU extraction
More stuff for IMU extraction
Adds flag to extract IMU information
Fixes some small errors with the new additions.
the error message is wrong for now, and makes it seem like things didn't work even if they did. Might want to make it actually work sometime in the future though.
Files saved in output dir. Timestamps stored with higher precision
Merge pull request #55 from arpg/feature/logtool-imu

ximea phi device_time is improperly formatted though.