Add badges for github.

Further more this closes apache#2 from github because it has already been
fixed in revision 1602206.


git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1706543 13f79535-47bb-0310-9956-ffa450edef68

Author: britter

CONTRIBUTING.md

@@ -41,6 +41,9 @@
 Contributing to Apache Commons CSV
 ======================
 
+[![Maven Central](https://maven-badges.herokuapp.com/maven-central/org.apache.commons/commons-csv/badge.svg)](https://maven-badges.herokuapp.com/maven-central/org.apache.commons/commons-csv/)
+[![License](http://img.shields.io/:license-apache-blue.svg)](http://www.apache.org/licenses/LICENSE-2.0.html)
+
 You have found a bug or you have an idea for a cool new feature? Contributing code is a great way to give something back to
 the open source community. Before you dig right into the code there are a few guidelines that we need contributors to
 follow so that we can have a chance of keeping on top of things.