Modified resource retrieval from gs_catalog in layers/models.py and added assumption that store exists within workspace in updatelayers to improve speed.
Merge remote-tracking branch 'upstream/master' into layer_geoserver_speedup
Updated code to obtain gs_resource in models(layers) to use gsconfig get_resource function with workspace and store passed.  Fixed issue with gs_slurp and error handling for nonexistent workspaces
Remove some unnecessary debug lines
Fixed issue with var reference names in get_resource() call in Layer.store_type property function
Merge branch 'master' into layer_geoserver_speedup
Merge branch 'master' of https://github.com/GeoNode/geonode
 Merge branch 'master' of https://github.com/GeoNode/geonode
Merge branch 'master' of https://github.com/GeoNode/geonode
Changed Django get params used in wms_links lookup to move url to defaults dict.  Prevents duplicate WMS links via repeated updatelayers calls
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
Updated changelog for version 2.0c6