Add entity to estimate the joint torque sensor offsets.

* [torque-offset-estimator] remove hardcoded joint values

* [MINOR] *check gyro values only when calibrating.
	*change unittest check message
	* add plugin to src/CMakeLists

* [MINOR] * change indentation
	* change init to take joint names instead of joint indices
	* remove joint remapping. use the urdf joint order directly

Conflicts:
	CMakeLists.txt
	src/CMakeLists.txt