Select / Summarize Non-EPC Tracts

[nataliemakhijani]

From sfcta/epc-map#14

Provide ability to select non-EPC tracts and get stats for those, too.

[nataliemakhijani]

New data must be uploaded to our API server containing data for all tracts in San Francisco. We have this data, but it is not in the server yet.

It needs to be decided whether this data will exist as a separate resource or if this data and the current EPC-tract-only data and it should be merged, tagging EPC tracts.