stablerange: warm cache on transaction (if obshashrange is enabled) If we plan to use it (obshashrange is enabled) we better keep it up to date. If a transaction adds node, we update the cache (this should also update the on disk version).

# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)