Update build status image in README to SVG

Author: weavejester

README.md

@@ -1,6 +1,6 @@
 # Compojure
 
-[![Build Status](https://secure.travis-ci.org/weavejester/compojure.png)](http://travis-ci.org/weavejester/compojure)
+[![Build Status](https://travis-ci.org/weavejester/compojure.svg?branch=master)](https://travis-ci.org/weavejester/compojure)
 
 Compojure is a small routing library for [Ring][1] that allows web
 applications to be composed of small, independent parts.