Changed build tool from Ant to Maven.

Main reason: Didn't want to keep dependencies (jars) in version control.

Don't know Ivy very well. Know Maven better. Don't know Gradle.

Changed the project structure to the Maven standard structure.

Deleted the Ant build.xml and the dependency jars.

Improved the README slightly.
Fixed build warning and updated README slightly.
Merge pull request #2 from betrcode/master

Changed build tool from Ant to Maven