The command ResumeAfterSafetyInterlock and the attribute SafetyChainOK do not work!
The underlying robot software has to be corrected.

command ResumeAfterSafetyInterlock.

get_sample_position()

Speed setting is not possible and checking the robot power when moving blocks the server.

Conflicts:
	SampleChangerDS/TomoSampleChanger.py

Attention: __metaclass__ = DeviceMeta is deleted by Pogo but necessary
to run the server!!!!!

Attention: __metaclass__ = DeviceMeta gets deleted by Pogo but is necessary
to run the server!!!!!

when entering the hutch. The movement will resume when
the hutch is closed.

tomo_sc_open_gripper, tomo_sc_open_gripper.
Modified the motor calibration macros init_mr_yrot and init_mr_sz. Need to
add a real limit check in those macros.

the attribute SafetyChainOK.

Added SafetyChainOK attribute. Prepared state handling for the safety chain, but
did not put it operation. Needs some testing on the behavior before.

recovery

Better sample handling.