COMP: Fix Travis CI test script

.travis.yml

+sudo: false
+
 language: cpp
 
+os:
+  - linux
+  - osx
+
 compiler:
   - clang
   - gcc
@@ -21,4 +27,7 @@ before_script:
 script:
   - cmake ../SuperElastix/SuperBuild
   - make --jobs=2 | grep -v '^--' | grep -v '^Installing'
-  - make test
+
+after_sucess:
+  - cd Elastix-build
+  - ctest