Changed dir sep from windows to unix

.travis.yml

@@ -27,8 +27,8 @@ before_script:
   # ino needs files in src directory
   - ln -s Marlin src
   - mkdir lib
-  - ln -s ..\ArduinoAddons\Arduino_1.0.x\libraries\SdFat lib\SdFat
-  - ls -la lib\SdFat
+  - ln -s ../ArduinoAddons/Arduino_1.0.x/libraries/SdFat lib/SdFat
+  - ls -la lib/SdFat
   # remove Marlin.pde as it confuses ino after it finds Marlin.ino
   - rm Marlin/Marlin.pde
 script: