* Add install4j support to the Maven build.

Using the 'install4j' profile on a server that has a suitable install4j and JREs, Maven can now
generate install4j builds, using: mvn -P install4j clean package

Note that Maven, even without the install4j profile, will no longer output the build artifacts
in /target. Instead, these are now outputted into /distribution/target/distribution-base/

* Make Ant build work with changed Maven structure.