normalize county/precinct names in shapefiles

[jamesturk]

on upload perhaps?
or via a transform w/ options

an alternative would be to have a state-wide setting for these on core.models.State

once this is done:

• the county and precinct name can be displayed again: https://github.com/OpenPrecincts/openprecincts-web/blob/master/raw_static/js/precinct-map.js#L246
• the dropdown managed here https://github.com/OpenPrecincts/openprecincts-web/blob/master/raw_static/js/mergetool.js#L272 is unnecessary

[jamesturk]

bonus: if this were done, the field-select code in the matching tool could be removed