Watney Rover -- remix

I'm listing this as a remix and a work in progress.

At this point it's the basic rover, I haven't mounted a camera yet. The quick assembly was to evaluate performance issues. Comments have been made about performance on carpet. The rover runs fine straight on carpet, but has trouble turning which seems to be a motor torque issue. I want to measure current to see if it's a current limit issue or something else. I also want to experiment with other turn algorithms other than the current full sp