methods now return a "branched" version so that the :meth:`.Connection.close`
method can be called on the returned connection without affecting the
original. Allows symmetry when using :class:`.Engine` and
:class:`.Connection` objects as context managers.
become an externally usable package but still remains within the main sqlalchemy parent package.
in this system, we use kind of an ugly hack to get the noseplugin imported outside of the
"sqlalchemy" package, while still making it available within sqlalchemy for usage by
third party libraries.