Proposed bugfix for Issue 48

Hello, we are using ReportNG at Jive Software and love it -- thanks for creating it.

This pull request contains a bugfix to Issue 48.

The bugfix lives *only* in **overview.html.vm**. Please ignore any changes I've made to **pom.xml** and **build.xml**. Those two files were modified so I could build ReportNG locally, and are NOT meant to be submitted as part of the bugfix. I just couldn't figure out a way to exclude them from the pull request.

I've tested the bugfix with code that lives on GitHub at jivesoftware/reportng-test. Feel free to take a look if you want; it works fine.

Chris Cowell-Shah / Jive Software
chris.cowell-shah@jivesoftware.com