Rewrites OncillaTrunk interface

Now it derives from TranslationalAccelerationSensing and
OrientationSensing, as it would be the data that we would get from the
fusion of a 9 DoF IMU (Accelerometer + Gyroscope + Magnetometer),
with, for example, an Extended Kalman Filter (EKF).

There is no interface for the raw data and this new interface is left
unimplemented.

amarsi_closes #238 amarsi_refs #478