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()

xml_func.py: process(): Added pass-through optimization for aggregating functions with one arg

xml_func.py: process(): Call list() on the items' iterator so that its length can be determined wherever it's used without needing to call list() on it separately

sql.py: mk_select(): Put '*' on same line as 'SELECT' if there is no DISTINCT ON, to avoid extra newlines

sql_gen.py: NamedTable.to_str(): Put AS clause on same line as code being named if it didn't contain a newline, to avoid extra newlines