To increase the similarity between this module and CPythons sqlite3 module
the commit() and rollback() as defined in CPythons version have been
added, along with the different (auto)commit behaviors present there.
The defaults are also set to the same as in CPython, and can be changed
with the same parameters in connect(), as is showcased in the new test.
Signed-off-by: Robert Klink <rhermanklink@ripe.net>