sql.py: add_col(): Document that name may be versioned, so caller needs to propagate any renaming back to any source column for the TypedCol

sql.py: add_col() callers: Removed column name versioning because that is now handled by add_col()

sql.py: add_col() callers: Fixed bug where needed to propagate any renaming of typed column back to regular column

sql.py: add_col(): Version column names to avoid collisions. (Previously, callers were required to do this themselves.)

sql.py: cast_temp_col(): Handle column name collisions like add_index_col()

sql.py: mk_insert_select(): INSERT IGNORE: Switched to using FOR loop rather than cursors because cursors are only needed if you want to process multiple rows in the same EXCEPTION block (which you can't do because then all the previous inserts will be rolled back if one row is a duplicate key)

sql.py: mk_insert_select(): INSERT IGNORE: Moved FETCH FROM cursor outside EXCEPTION block since only the insert needs to have unique_violations ignored

sql.py: put_table(): Removed no longer needed EXCLUSIVE lock on the output table

add_index_col(): Run all operations with log_level=3 because it is the equivalent of creating an index, and that has log_level=3 to be excluded from the primary algorithm steps. add_not_null(): Run query with log_level=3 because it's an internal operation and for add_index_col() above.

sql.py: update(): Pass any log_level to run_query()