FEATURE: CORE-2204 - Add polygon and point as new datatypes to DataSpace

QA: This API isn't used by the frontend currently so there shouldn't be any UI-facing changes to test.
Replace Line/Polygon with MultiLine/MultiPolygon
Use WKT for transport within DSS instead of GeoJSON. GeoJSON is still the client-facing format.
Merge branch 'master' of http://github.com/socrata/soda-fountain into CORE-2204
Merging before checking in changes for Dataspace to speak Geo.