test "default" section

.gitlab-ci.yml

+default:
+    image: rboman/waves
+
 stages:
     - build
     - test
 
 build_gcc:
-    image: rboman/waves
     stage: build
     script:
         - source /opt/intel/mkl/bin/mklvars.sh intel64
@@ -20,7 +22,6 @@ build_gcc:
         expire_in: 1 hour
 
 doxygen:
-    image: rboman/waves
     stage: test
     script:
         - cd build
@@ -31,7 +32,6 @@ doxygen:
         expire_in: 1 day
                   
 ctest:
-    image: rboman/waves
     stage: test
     script:
         - source /opt/intel/mkl/bin/mklvars.sh intel64