Add travis helper update_defaults

.travis.yml

   - export TEST_PLATFORM="-e teensy35"
   - restore_configs
   - opt_set MOTHERBOARD BOARD_TEENSY35_36
-  - cp Marlin/Configuration.h Marlin/src/config/default/Configuration.h
-  - cp Marlin/Configuration_adv.h Marlin/src/config/default/Configuration_adv.h
+  - update_defaults
   - cp Marlin/src/pins/pins_RAMPS.h Marlin/src/pins/pins_RAMPS.h.backup
   #
   # Test Teensy3.5 with default config
   - restore_configs
   - opt_set MOTHERBOARD BOARD_RAMPS4DUE_EFB
   - opt_set S_CURVE_ACCELERATION
-  - cp Marlin/Configuration.h Marlin/src/config/default/Configuration.h
-  - cp Marlin/Configuration_adv.h Marlin/src/config/default/Configuration_adv.h
+  - update_defaults
   - build_marlin_pio ${TRAVIS_BUILD_DIR} ${TEST_PLATFORM}
 
   #############################
   - export TEST_PLATFORM="-e LPC1768"
   - restore_configs
   - opt_set MOTHERBOARD BOARD_RAMPS_14_RE_ARM_EFB
-  - cp Marlin/Configuration.h Marlin/src/config/default/Configuration.h
-  - cp Marlin/Configuration_adv.h Marlin/src/config/default/Configuration_adv.h
+  - update_defaults
   - build_marlin_pio ${TRAVIS_BUILD_DIR} ${TEST_PLATFORM}
   #
   # Enable VIKI2, SDSUPPORT
   #
   - restore_configs
   - opt_set MOTHERBOARD BOARD_RAMPS_14_RE_ARM_EFB
-  - cp Marlin/Configuration.h Marlin/src/config/default/Configuration.h
-  - cp Marlin/Configuration_adv.h Marlin/src/config/default/Configuration_adv.h
+  - update_defaults
   - opt_enable VIKI2 SDSUPPORT
   - build_marlin_pio ${TRAVIS_BUILD_DIR} ${TEST_PLATFORM}

buildroot/bin/update_defaults

+#!/usr/bin/env bash
+
+cp Marlin/Configuration.h     Marlin/src/config/default/Configuration.h
+cp Marlin/Configuration_adv.h Marlin/src/config/default/Configuration_adv.h