Detecting and reacting to MultiTurn mode

[FranzEricSchneider]

Hi,

The Dynamixels I'm working with (new MXs) can be set to Joint Mode, Wheel Mode, and MultiTurn Mode. When in MultiTurn Mode, both the CCW and CW angle limits are set to 4095. When in MultiTurn Mode the angle limits are not 0-1023, as they are in Joint Mode, but are instead -22,000 (something in the 22,000 range) to 22,000. The problem is, dynamixel_controllers code does not detect MultiTurn mode and sets the min and max angles inside of dynamixel_controllers to 0-1023, artificially limiting the motors.

Can either MultiTurn mode be checked for (should be easy with the 4095 angle limits) or can the max and min be passed in?

[dbolkensteyn]

This PR provides a good implementation for the multi-turn mode https://github.com/arebgun/dynamixel_motor/pull/68