Spool holder wheel remix

###This is a remix of Mike-vom-Mars' Ultra-Smooth Running Spool Holders.
###The wheel is now in 2 identical halves which can be glued together and you can insert 3mm diameter BBQ skewer pieces in the holes to align the 2 halves.

###This also fixes the problem of the step in the original design which caused problems printing the 2nd layer.

###Just print 2 of these for each wheel.