Only show categories that will return locations

Not all 327 OE categories have been assigned to locations, so we should only show those that will actually return results. This is hardcoded for now, but the API will provide this info soon.
Merge branch 'master' into kind-category-filter
Removes unused code

Deleted code was part of a branch that used it for pagination, however
it is no longer needed with the merged code from master.