(V2.1) [gCrd] does not work when servos are detached

[apockill]

Bug:
The [gCrd] command does not work when the servos are detached- it only returns the last known position.

Expected Result:
If I have all of the servos detached, and I move the robot, I should get the current location of the end effector even if the servos are detached and the robot has been moved.

Steps to reproduce bug:

1. Unplug robot from power and computer.
2. Plug the robot into power and computer
3. Enter "[gCrd]", record response. I got: "[SX-95.83Y0.00Z145.10]"
4. Enter "[sDetN0][sDetN1][sDetN2][sDetN3]"
5. Move the end effector to a different location
6. Enter "[gCrd]". I got "[SX-95.83Y0.00Z145.10]", which is the same thing that I got in step 3 even though the robot was moved.

[yuntian1019]

Fixed in vertion 2.1.1.
2.1.0 return the position of last move.