The "artifact:dependencies" task has no way to filter based on dependency type (ie. jar, tld, etc...)

Currently the only filter that can be applied to the "artifact:dependencies" task is the scope.
It would be useful to be able to filter the artifact type, so that you can retrieve related sets
of dependencies, such as TLD files for inclusion into a .war file.

I am going to attach a new file "TypeArtifactFilter.java" along with a diff file for DependenciesTask.java
which will add this functionality to the task.

Both of these belong in the org.apache.maven.artifact.ant package (though TypeArtifactFilter could
potentially reside in the "artifact" component)

I'm not really sure how testcases are done for the tasks, but i can look into it. it's a relatively simple
change and something that's easy to check for.