Add maven badge

Author: laurynas

README.md

@@ -1,8 +1,10 @@
 # Language Detection API Java Client
 
+[![Maven metadata URI](https://img.shields.io/maven-metadata/v/http/central.maven.org/maven2/com/detectlanguage/detectlanguage/maven-metadata.xml.svg)](https://mvnrepository.com/artifact/com.detectlanguage/detectlanguage)
+[![Build Status](https://secure.travis-ci.org/detectlanguage/detectlanguage-java.svg)](http://travis-ci.org/detectlanguage/detectlanguage-java)
+
 Detects language of given text. Returns detected language codes and scores.
 
-[![Build Status](https://secure.travis-ci.org/detectlanguage/detectlanguage-java.png)](http://travis-ci.org/detectlanguage/detectlanguage-java)
 
 ## Installation