Unit tests may fail due to modified preferences

[jwt388]

The expected results of the arm unit tests are based on default preference values. One of the preferences is changed in the arm subsystem test. It is also possible that preferences changed in simulation mode will cause test failures. Since the order that the unit tests are run isn't known or fixed, the behavior may be different at different times.

[jwt388]

Added function to reset preferences which is called before each test. Also moved log preferences function into a utility class with the reset to start consolidation of preference handling functions. Removed test steps that try to modify preferences since this is unpredictable with tests running in parallel. Increased time for arm settling based on using default Kp.