Log Message:
Update py-bsddb3 to 4.1.6.

Changes sinec 4.1.1:
 * 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.
 * Updated documentation for set_get_returns_none.  Regenerated the
   stale html docs from the text documentation.
 * 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.
 * Added the dbobj wrapper for DBEnv set_timeout method.
 * Updated README.txt
 * Added the DBEnv.set_timeout method.
 * code cleanup to use python 2.x features in .py files
 * the standalone pybsddb distribution will install a module
   called bsddb3 while the module included with python >= 2.3
   will be known as bsddb.
 * Shared all .py and .c source with the Python project.
 * Fixed DBTxn objects to raise an exception if they are used after
   the underlying DB_TXN handle becomes invalid. (rather than
   potentially causing a segfault)
 * Fixed module to work when compiled against a python without thread
   support.
 * Do not attempt to double-close DB cursor's whos underlying DB
   has already been closed (fixes a segfault).
 * Close DB objects when DB.open fails to prevent an exception about
   databases still being open when calling DBEnv.close.