remove SRID which is not needed in CSW context
update travis-ci link [ci skip]
Added a migration to remove SRID from default value in the ResourceBase csw_wkt_geometry field.
Removed the thumbnail field from the LayerForm.
Dont fail miserably in cascading_delete if the workspsace is not found
Add store_type property to layer model
Removed the default_style and styles fields from the LayerForm