index: drop support for negative indexes into the index
I want index[i] to work for any valid revnum including -1 (as it
already does), and I also want len(index) to be the number of
revisions in the index (not counting the null revision), so it cannot
also support negative revision numbers other than -1 for nullid.
I didn't bother removing support for it from revlog v0.
Differential Revision: https://phab.mercurial-scm.org/D4019
# name space package to host third party extensions
from __future__ import absolute_import
import pkgutil
__path__ = pkgutil.extend_path(__path__, __name__)