* Extended DB & DBEnv set_get_returns_none functionality to take a
"level" instead of a boolean flag. The boolean 0 and 1 values still
have the same effect. A value of 2 extends the "return None instead
of raising an exception" behaviour to the DBCursor set methods.
This will become the default behaviour in pybsddb 4.2.
* Fixed a typo in DBCursor.join_item method that made it crash instead
of returning a value. Obviously nobody uses it. Wrote a test case
for join and join_item.
underlying DB has already been closed (and thus all of its cursors).
This fixes a potential segfault.
SF pybsddb bug id 667343
bugfix: close the DB object when raising an exception due to an error
during DB.open. This prevents an exception when closing the
environment about not all databases being closed.
SF pybsddb bug id 667340