Let's get some nice mocha integration

Maybe that's by using the TPP output (or whatever it is), or a custom formatter, but it would be awesome to have:
- a count of number passed/failed/skipped at the _top_ of the test
- collapse the logs for individual test cases, so you don't have to wade through a ton of stuff
- maybe even collapse describe()s that are all passing

Start by finding how Mocha test output is currently collected and whether the project uses TPP output or a custom formatter. Compare the available output paths against the requested summary, collapsible test logs, and collapsible passing describe() blocks. Done means the integration presents those reporting improvements without requiring users to wade through every passing test log.

Written by the indexing model from the issue text.