Add scripts for .travis.yml to append config options

.travis.yml

   - opt_set_adv I2C_SLAVE_ADDRESS 63
   - opt_enable_adv ADVANCED_PAUSE_FEATURE PARK_HEAD_ON_PAUSE LCD_INFO_MENU
   - pins_set RAMPS X_MAX_PIN -1
-  - opt_set_adv Z2_MAX_PIN 2
+  - opt_add_adv Z2_MAX_PIN 2
   - build_marlin
   #
   # Enable COREXY

buildroot/bin/opt_add

+#!/usr/bin/env bash
+
+eval "echo \"#define ${1} ${2}\" >>Marlin/Configuration.h"

buildroot/bin/opt_add_adv

+#!/usr/bin/env bash
+
+eval "echo \"#define ${1} ${2}\" >>Marlin/Configuration_adv.h"