Changes to support election day vote centers.

lib/voteatx/finder.rb:
- Hacked up VoteATX::Finder#search to return election day results.

lib/voteatx/loader.rb:
- Added new "voting_precincts" table.
- Removed "voting_places.precinct" column.
- Changed precinct handling in load_eday_places method.
- The election day voting places spreadsheet can now have an empty PCT column (for an election day vote center).
- Deprecated VoteATX::VotingPlacesLoader#explode_combined_precincts property.

lib/voteatx/place.rb:
- Fixed VoteATX::ElectionDay.find_by_precinct to work with new "voting_precincts" table.
- Dropped VoteATX::ElectionDay.find_by_precinct to work with new "voting_precincts" table.
- Dropped VoteATX::ElectionDay.find_by_location method.
- New VoteATX::ElectionDay.search method.
In info window, move election day voting place info from "notes" to "title".
In info window, add vote center info to "notes".