Add more syntax support for SQL query generation
Add more syntax support for SQL query generation

1. Add basic 'HAVING' clause (before the 'ORDER BY' clause).
2. Select source tables in 'DATE_RANGE' format.
3. Add 'BETWEEN' clause in conditions.
4. Modify 'ORDER BY' to accept multiple parameters.

hagino3000/BigQuery-Python,tylertreat/BigQuery-Python