* Create query_obj for every filter
* Deprecate is_prequery and prequeries from query_obj
* Fix tests
* Fix typos and remove redundant ; from sql
* Add typing to namedtuples and move all query str logic to one place
* Fix unit test
* Add extra_require for bigquery to setup.py
* Refactor df_to_db and add df upload capability for BigQuery
* Fix unit tests and clarify kwarg logic
* Fix flake8 errors
* Add minimum versions for bigquery dependencies
* wrap to_gbq in try-catch block and raise error if pandas-gbq is missing
* Fix linting error and make error more generic