Add GeoScript Groovy to the Community Groovy Script Module

This is a pull request to add GeoScript Groovy to the Community Groovy Script module.  Here is what I added:

1. The Community Groovy Script module now depends on GeoScript Groovy 1.1-SNAPSHOT which depends on GeoTools 9-SNAPSHOT.

2. The WPS and Function extention points convert input GeoTools objects to GeoScript objects so you can use GeoScript in the script and then convert the return GeoScript objects back to GeoTools objects.

3. I added a simple GeoServer GeoScript Groovy API based on the Python and JavaScript examples.

       * geoserver.GeoServer
       * geoserver.Config
       * geoserver.catalog.Catalog
       * geoserver.catalog.Workspace
       * geoserver.catalog.Store
       * geoserver.catalog.Layer


The GeoServer GeoScript API includes unit tests written in Groovy.

This is must first non-trivial pull request for GeoServer, so if I did anything wrong or if needs any improvements please let me know!

In late December, I gave a presentation at CUGOS about this work and it contains more examples.

https://docs.google.com/open?id=0B8cwqNmbcThpNkRKT0VDc3V6Q0E

Thanks,
Jared Erickson