Fixed non powered motor problem

range(3) does 0, 1, 2. Not 0, 1, 2, 3. You want range (4)
Added motor stepping so power rail doesnt fall out on startup

Added a brief sleep between turning on all the motors which allows for
the current surge not to be so big to lower the power rail.
Merge pull request #1 from Ultimation/master

Fixed the missing motor power problem. Range is not the limit, but how many.