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/BIGTREE_BTT002

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+#
+# Build tests for STM32F407VGT6 BigTreeTech BTT002 V1.0
+#
+
+# exit on first failure
+set -e
+
+#
+# Build with the default configurations
+#
+restore_configs
+opt_set MOTHERBOARD BOARD_BTT_BTT002_V1_0 \
+        SERIAL_PORT 1 \
+        X_DRIVER_TYPE TMC2209 \
+        Y_DRIVER_TYPE TMC2130
+exec_test $1 $2 "BigTreeTech BTT002 Default Configuration plus TMC steppers" "$3"
+
+#
+# A test with Probe Temperature Compensation enabled
+#
+use_example_configs Prusa/MK3S-BigTreeTech-BTT002
+exec_test $1 $2 "BigTreeTech BTT002 with Prusa MK3S and related options" "$3"
+
+# clean up
+restore_configs