updated README.md with travis ci build badge

README.md

@@ -1,5 +1,7 @@
 Welcome to the Zend Framework 1.12 Release! 
 
+Master: [![Build Status](https://travis-ci.org/zendframework/zf1.png?branch=travis-ci)](https://travis-ci.org/zendframework/zf1)
+
 RELEASE INFORMATION
 ===================