Fix u8g.h search path error (#10419)

Support env MARLIN_LANGS for user select generated language, and update doc; update script to generate dogm_font_data_ISO10646_1.h automatically.

.travis.yml

@@ -43,6 +43,10 @@ before_script:
   - cat ${TRAVIS_BUILD_DIR}/Marlin/src/inc/_Version.h
   #
 script:
+  #
+  # Fix include path problem in platformio.ini, U8glib-HAL_ID1932/src/lib/u8g.h
+  #
+  - find Marlin/ -name "*.h" | while read a; do sed -e 's|clib/u8g.h|u8g.h|' -i "$a"; done
   #
   # Backup pins_RAMPS.h
   #