FGDC Topic Category extraction
Assigns TopicCategory to Layer using extracted metadata.
Added category_list to advanced search context for category filter
Added category filter
Added support for capturing multiple keywords from FGDC metadata.
added OL to search
added UI for search by extent
UI cleanup for extent search
added extent filter to search results page
removed extra openlayers in favor of OL wrapped in ExtGeo
added geoexplorer JS packages in search templates and wrapped in Ext
Added a migration for adding the new base.license model.
Add the SOCIAL_BUTTONS setting to context_processors.
Merge branch 'searchmap' of https://github.com/nathanhilbert/geonode into nathanhilbert-searchmap
Added Nathan Hilbert to AUTHORS

He contributed extent based search.
Fix spelling error and remove duplicate entry in AUTHORS.
Fixed merge conflict
Merge branch 'master' of github.com:GeoNode/geonode
Added Elliot Bradbury to AUTHORS

He added ISO topics to search form
Fixed the migration's documentation.