Add Maven central badge

Author: István Karaszi

README.md

@@ -9,6 +9,7 @@ for console based Java applications.
 The inspiration came from visionmedia's [node-progress][1].
 
 [![Build Status](https://travis-ci.org/raszi/java-progressbar.svg?branch=master)](https://travis-ci.org/raszi/java-progressbar)
+[![Maven Central](https://img.shields.io/maven-central/v/hu.ssh/java-progressbar.svg?label=Maven%20Central)](https://search.maven.org/search?q=g:%22hu.ssh%22%20AND%20a:%22java-progressbar%22)
 
 ```xml
 <dependency>