sql.py: put_table(): "Ignoring existing rows, comparing on" debug message: Wrap the mapping in strings.as_code() so it will have Redmine syntax-highlighting

sql.py: put_table(): "Putting columns" debug message: Wrap the mapping in strings.as_code() so it will have Redmine syntax-highlighting

sql.py: DbConn.run_query(): Query debug message: Wrap the query in strings.as_code() so it will have Redmine syntax-highlighting

strings.py: Added as_code()

sql.py: DbConn.run_query(): Prepend "DB query" before the query debug message so it can be identified as a DB query

db_xml.py: put_table(): Subset in_table: Document that in_table will be shadowed (hidden) by the created temp table, rather than versioned, now that the table is (almost) always created as a temp table

sql.py: Create temp items as permanent in autocommit mode rather than in debug mode so that temp items are only permanent if actually committing result. This ensures that the generated SQL in test mode matches what would actually get run in regular commit mode, and the SQL is only altered to make the temp items visible if actually debugging (autocommit mode).

sql.py, sql_gen.py: Reformatted generated SQL for presentability by adding newlines

sql.py: DbConn.run_query(): Put a newline before the query in the debug message so that multiline queries have all rows at the left edge rather than the first row prefixed by other text

sql.py: DbConn.run_query(): Don't put generated query debug message all on one line, so that embedded newlines are preserved