Add Marlin firmware. Has initial configuration for CoreXY and 1 servo.

Update CAD file with improved clearances for Pilot G2 cartridge clearances after first print.

Marlin Firmware/buildroot/bin/use_example_configs

@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+
+IFS=: read -r PART1 PART2 <<< "$@"
+[ -n "${PART2}" ] && { REPO="$PART1" ; RDIR="${PART2// /%20}" ; } \
+                  || { REPO=bugfix-2.0.x   ; RDIR="${PART1// /%20}" ; }
+EXAMPLES="https://raw.githubusercontent.com/MarlinFirmware/Configurations/$REPO/config/examples"
+
+which curl >/dev/null && TOOL='curl -L -s -S -f -o wgot'
+which wget >/dev/null && TOOL='wget -q -O wgot'
+
+restore_configs
+
+cd Marlin
+
+$TOOL "$EXAMPLES/$RDIR/Configuration.h"     >/dev/null 2>&1 && mv wgot Configuration.h
+$TOOL "$EXAMPLES/$RDIR/Configuration_adv.h" >/dev/null 2>&1 && mv wgot Configuration_adv.h
+$TOOL "$EXAMPLES/$RDIR/_Bootscreen.h"       >/dev/null 2>&1 && mv wgot _Bootscreen.h
+$TOOL "$EXAMPLES/$RDIR/_Statusscreen.h"     >/dev/null 2>&1 && mv wgot _Statusscreen.h
+
+rm -f wgot
+cd - >/dev/null