rolling build at appveyor for master branch only for now

appveyor.yml

@@ -13,6 +13,9 @@ install:
   - cmd: SET PATH=C:\maven\apache-maven-3.2.5\bin;%JAVA_HOME%\bin;%PATH%
   - cmd: SET MAVEN_OPTS=-XX:MaxPermSize=2g -Xmx4g
   - cmd: SET JAVA_OPTS=-XX:MaxPermSize=2g -Xmx4g
+branches:
+  only:
+    - master
 #build C# solution and scala project
 build_script:
 - cmd: >-