Use maven ant tasks for resolving dependencies.

Currently the generated maven-build.xml file uses the <get> task to try to download each dependency. This can be very slow especially because a separate <get> is created for each repository, so the build has to wait for several timeouts. A better solution might be to use the maven ant tasks. That way the dependency resolution behaves the same way as the maven build. The ant plugin could resolve the ant tasks jar to the local maven repo, and then add the necessary configuration to the generated maven-build.xml.