Don't allow sorting on geo_point
In discover, if you add a field of type geo_point to your search, and then try to sort on that field, the app errors out. It doesn't make sense to allow sorting on geo_point as this is not supported by ElasticSearch. Perhaps in the future we can allow sorting geo_point by distance from a given location.
Don't allow sorting on geo_shape or attachment either
Merge pull request #1940 from lukasolson/issue-1933

Don't allow sorting on unsortable field types