remove vpf etension GEOT-2347

The VPF module has not been migrated to the GeoTools 2.5 feature model.

See https://jira.codehaus.org/browse/GEOT-2347 for details

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>
Remove vpf reference used by assembly step

Signed-off-by: Jody Garnett <jody.garnett@gmail.com>
Merge pull request #312 from jodygarnett/remove_vpf

remove vpf etension GEOT-2347