make clean added at start of every engine build
diff --git a/.travis.yml b/.travis.yml
index f198940..3fa925c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -36,17 +36,17 @@
   
 script:
   - cd nlp-ner-engine
-  - make marvin
+  - make clean marvin
   - marvin test
   - cd ..
   - cd sms-spam-engine
-  - make marvin
+  - make clean marvin
   - marvin test
   - cd ..
   - cd iris-species-engine
-  - make marvin
+  - make clean marvin
   - marvin test
   - cd ..
   - cd mnist-keras-engine
-  - make marvin
+  - make clean marvin
   - marvin test