Cut version 0.0.1b8

Cut version 0.0.1b8

- Docs for Graph.
- Adds Graph.
- Tiebreak ordering of ranges with the same lower bound using upper bound.
- More docs...
- More docs.
- Update docs again.
- Update docs and type hints in interval_tree.  Add it to the pydocs.
- Fix interval_tree so it actually works.  Add unittests.
- Bug and readability fix.
- Adds IntervalTree.
- Remove more annoying warning messages dumped to console from library code.
- Be less annoying.
- Make argparse utils' valid_date work with the default format of UNIX date.
- Improve identifier for zookeeper based lockfiles.
- Adds support for zookeeper-based lockfiles.
- Make the processed cmdline available to callers.
- Fixup/improve error message when giving up on lock acquisition.
- Improve error message for logs.
- Do not touch timestamp if cronjob failed!
- Fix docs.
- Only upload one wheel.
- Update docs.
- Update docs.
- Tweak cut_version.sh again.
- Cut version 0.0.1b7