Add Travis test for scrolling on DOGM

.travis.yml

   - opt_set_adv SDSORT_CACHE_NAMES true
   - build_marlin
   #
-  # REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
+  # REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER with SDCARD_SORT_ALPHA and STATUS_MESSAGE_SCROLLING
   #
   - restore_configs
   - opt_enable REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER SDSUPPORT
+  - opt_enable_adv SDCARD_SORT_ALPHA STATUS_MESSAGE_SCROLLING
   - build_marlin
   #
   # REPRAPWORLD_KEYPAD