py3: make keys of keyword arguments strings
keys of keyword arguments on Python 3 has to be string. We are dealing with
bytes in our codebase so the keys are also bytes. Done that using
pycompat.strkwargs().
Also after this patch, `hg version` now runs on Python 3.5. Hurray!
# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)