Added flag for partial models (when fields is passed to ModelMapper.fetch).
Fixed bug where partial models would keep unused fields.
Fixed bug in ModelMapper.fetch that was causing it to ignore FieldMultiRef fields when passing fields.
Fixed bug in ModelMapperSqlite when query builder raises for partial models.
Simplified regex matching in WsgiRoute.
Added comparison function to Model.
Added cast from Model in sqlite._query_to_sql.