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/opt_enable

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+# exit on first failure
+set -e
+
+SED=$(which gsed sed | head -n1)
+
+for opt in "$@" ; do
+  DID=0 ; FOUND=0
+  for FN in Configuration Configuration_adv; do
+    "${SED}" -i "/^\(\s*\)\/\/\(\s*\)\(#define\s\+${opt}\b\)\( \?\)/{s//\1\2\3\4\4\4/;h};\${x;/./{x;q0};x;q9}" Marlin/$FN.h && DID=1
+    ((DID||FOUND)) || { grep -E "^\s*#define\s+${opt}\b" Marlin/$FN.h >/dev/null && FOUND=1 ; }
+  done
+  ((DID||FOUND)) || (echo "ERROR: $(basename $0) Can't find ${opt}" >&2 && exit 9)
+done