PlotClock 3d printed

PlotClock build based on Joo's original & Harlan's modifications

Modifications:
Expanded body for greater stability/durability
changed arms & wiper
made to use small screws I had on hand
holds a Quartet marker
use 10D nail for pivot on lift axis, little plug to keep it in if it's loose...
Mouser ears on body because one edge was lifting off my platform

note: error in comments for calibration as per http://www.thingiverse.com/thing:931498
// When in calibration mode, adjust the NULL-