Enable travis support for stable branch

.travis.yml

@@ -6,6 +6,7 @@
 branches:
   only:
   - master
+  - stable
 dist: trusty
 language: cpp
 

travis/generate_travis.py

@@ -39,6 +39,7 @@ if __name__ == "__main__":
     s += "branches:\n"
     s += "  only:\n"
     s += "  - master\n"
+    s += "  - stable\n"
     s += "dist: trusty\n"
     s += "language: cpp\n"
     s += "\n"