Several recently merged webhooks were incorrectly not checking that
the actual webhook result didn't return an error. While they would
usually still fail in most cases when checking whether the message
came back correctly, this hid the root cause errors and thus made it
much harder to debug.
This integration relies on the Teamcity "tcWebHooks" plugin which is
available at
https://netwolfuk.wordpress.com/category/teamcity/tcplugins/tcwebhooks/
It posts build fail and success notifications to a stream specified in
the webhook URL.
It uses the name of the build configuration as the topic.
For personal builds, it tries to map the Teamcity username to a Zulip
username, and sends a private message to that person.
