This improves the ability of a bot to specify how to mention it,
which varies at run-time depending upon the identity used to run it;
this is commonly used in many bot help commands.
This program replaces zulip_bot_output.py, which had
gotten a little out of date.
It should be able to simulate a terminal conversation for
all of our bots, including those that use "advanced" features:
third party config files: tested with giphy
message updates: tested with incrementor
storage: tested with virtual_fs and others
