Dual Wiper for Lulzbot Mini

The Lulzbot Mini's standard felt pad cleaning strip works well to remove melted plastic, but often leaves a few felt fibers on the print head. Those fibers can prevent good electrical contact between the print head and bed washers, causing the G29 probe sequence to fail.

This is a re-design of the pad holder. In addition to holding the standard Lulzbot felt pad, a secondary slot holds a 71mm x 11mm strip of "Scotch Brite Non-Scratch Scour Pad". Adding a successive wipe across the non-fib