With the new repo, doing a `pip install -e ./zulip` will be a part
of the core workflow. This mitigates the risk of developers
accidentally testing their changes against an installed copy of the
zulip package rather than the copy in their checkout. Therefore,
we can now get rid of the various `sys.path.inserts` in the examples.
In order to keep all three packages (zulip, zulip_bots,
zulip_botserver) in the same repo, all package files must now
be nested one level deeper.
For instance, python-zulip-api/zulip_bots/zulip_bots/bots/, instead
of python-zulip-api/zulip_bots/bots/.
