Merge pull request #17 from enduro2d/hotfix/fix-ci-build

Hotfix/fix travis CI build

.travis.yml

@@ -45,4 +45,5 @@ script:
   - git submodule update --init --recursive
   - git lfs install
   - git lfs pull
+  - git submodule foreach git lfs pull
   - ./scripts/build_all.sh

BUILD_INSTRUCTIONS.md

@@ -14,6 +14,7 @@ $ git clone --recursive git://github.com/enduro2d/enduro2d-bootstrap.git
 $ cd enduro2d-bootstrap
 $ git lfs install
 $ git lfs pull
+$ git submodule foreach git lfs pull
 ```
 
 ## * Building