Copter: IMU and Baro are logged when launched.

With the new Linux-based boards (PXF, Erle-board, etc.) it's useful
to have the sensor configurations printed out when the autopilot is
launched. This patch prints IMU and Baro information.
Tools: Change sensor configurations easily.

This shell script allows to change the sensor configuration
(for now just supports IMU changes) so that the autopilot is
compiled for different combinations of sensors. This has probed
to be useful with Linux-based boards (e.g.: PXF, Erle-board)
that include serveral, different sensors for each kind.