- added a real unit test for sqlsoup

- added a real unit test for sqlsoup
- removed doctest stuff
- redid session docs for sqlsoup
- sqlsoup stays within the transaction of a Session now, is explcitly autocommit=False by default and includes commit()/rollback() methods
- sqlsoup db.<sometable>.update() and delete() now call
query(cls).update() and delete(), respectively.
- sqlsoup now has execute() and connection(), which call upon
the Session methods of those names, ensuring that the bind is
in terms of the SqlSoup object's bind.