try to fix path to additional libraries.

.travis.yml

   - sudo apt-get update -q 
   - sudo apt-get install arduino
 before_script:
+  # copy TMC and L6470 libraries to arduino dir, as conditional includes do not work in .ino files
+  - cp -r ArduinoAddons/Arduino_1.x.x/libraries/ /usr/share/arduino/libraries/  
  # add U8glib, LiquidCrystal_I2C & LiquidTWI2 libraries 
   - sudo unzip u8glib_arduino_v1.17.zip -d /usr/share/arduino/libraries/
   - cd /usr/share/arduino/libraries/
   - sudo rm -rf /usr/share/arduino/libraries/Robot_Control
   # change back to home directory for compiling
   - cd $TRAVIS_BUILD_DIR
-  # copy TMC and L6470 libraries to arduino dir, as conditional includes do not work in .ino files
-  - cp -r ../ArduinoAddons/Arduino_1.x.x/libraries/ /usr/share/arduino/libraries/  
   # ino needs files in src directory
   - ln -s Marlin src
   # remove Marlin.pde as it confuses ino after it finds Marlin.ino