Refactor PersistenceExpectations to contain multiple records

[landonreed]

Currently PersistenceExpectations allows tests to verify that an imported GTFS table has certain values, but it can only do this for one value. It currently selects all records in a table and just checks that each row meets the various record expectations, which just doesn't seem right. This should be refactored so that multiple records can be provided for a given table and the db selection checks each row accordingly.