…ement

The iterdump command in Lib/sqlite3/dump.py assumed that the table "sqlite_sequence" already exists. When this was not the case and exception was thrown.

# Conflicts:
#	Lib/sqlite3/test/dump.py

…es according to PEP 8

# Conflicts:
#	Lib/sqlite3/test/test_dump.py

…qlite3 dump tests

…l as small formatting changes in sqlite3/dump.py

…xed wrong use of double quotes and single quotes in sqlite3 statements

- consolidate construction of sqlite_sequence
- use existing quoting style

- reduce number of escape chars in string literals
- normalise variable names
- in test_dump_autoincrement_create_new_db, simplify setup
- use subTest in order to make it easier to assert more thoroughly