ENH: Filter boost copy command from Travis CI build log

.travis.yml

@@ -26,7 +26,7 @@ before_script:
 
 script:
   - cmake ../SuperElastix/SuperBuild
-  - make --jobs=2 | grep -v '^--' | grep -v '^Installing'
+  - make --jobs=2 | grep -v '^--' | grep -v '^Installing' | grep -v '^common'
 
 after_sucess:
   - cd Elastix-build