Test flipping track direction and running movers in a negative direction

[netbymatt]

Confirm that the instructions for flipping the direction of the track work on hardware. Then set up a sequence where movers need to travel around the track in the negative direction. i.e. station 1 = 1000mm, station 2 = 500mm, station 3 = 200mm, etc. There's some concern that position triggers default to positive only and may need an optional flag to flip the direction.

[pswift066]

Works as expected. Still needs documentation