Updated readme

Author: javagl

README.md

@@ -2,11 +2,21 @@
 
 A JTreeTable implementation.
 
+![JTreeTableScreenshot01.png](/screenshots/JTreeTableScreenshot01.png)
+
 This library is based on the code from the article "Creating TreeTables" by Sun 
 Microsystems (now known as Oracle). The original link to this 
 article was [http://java.sun.com/products/jfc/tsc/articles/treetable2/index.html](http://java.sun.com/products/jfc/tsc/articles/treetable2/index.html). It is
 not longer available, but may still be viewed in the [web archive](https://web.archive.org/web/20120626135631/http://java.sun.com/products/jfc/tsc/articles/treetable2/index.html)
 
+The library is available in Maven Central:
+
+    <dependency>
+      <groupId>de.javagl</groupId>
+      <artifactId>treetable</artifactId>
+      <version>0.0.1</version>
+    </dependency>
+