new harvester AODN-DSTO
added sspatial extent update component
Added sourceDir to context of main job
Renamed the contexts to match what is in the Google document
Activated the last subjob to update Geonetwork's SpatialExtent
Added GIST index and specified 4326 SRID on measurements table
Merge pull request #58 from aodn/aodn_dsto

new harvester AODN-DSTO