Update README with new name

Author: glibas

README.md

@@ -1,5 +1,7 @@
-[![Build Status](https://travis-ci.org/assertthat/selenium-screenshotter.svg?branch=master)](https://travis-ci.org/assertthat/selenium-screenshotter)
-# selenium-screenshotter
+# shutterbug
+
+[![Build Status](https://travis-ci.org/assertthat/shutterbug.svg?branch=master)](https://travis-ci.org/assertthat/shutterbug)
+
 Utility library to create customised screenshots using Selenium WebDriver
 
 _Work in progress ..._