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/tests/FLYF407ZG

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+#
+# Build tests for FLYF407ZG
+#
+
+# exit on first failure
+set -e
+
+# Build examples
+restore_configs
+opt_set MOTHERBOARD BOARD_FLYF407ZG SERIAL_PORT -1 X_DRIVER_TYPE TMC2208 Y_DRIVER_TYPE TMC2130
+exec_test $1 $2 "FLYF407ZG Default Config with mixed TMC Drivers" "$3"
+
+# cleanup
+restore_configs