Add missing API documentation for `IOutputExecutor.output` and fix the `output_` method signatures in the turnstile example.
Add a news fragment for this fix.

Hopefully this will feed into Twisted's `NewsBuilder` and make releases easier.
Worst case I'll manually concatenate a bunch of files...
Simplify.  I'll add real documentation for rich inputs real soon now, promise.
Merge pull request #11 from hybridcluster/rich-input-context-docs-9

Fix the `output_` signatures in the example to match what is actually required by machinist.
Mention that issues are tracked using waffle.io
Merge pull request #15 from cyli/fix_trivial_input

Fix for trivialInput so that instances produced are providers of IRichInput
Merge pull request #22 from adamtheturtle/point-at-waffleio-21

Mention that issues are tracked using waffle.io
Change FSM receive to receive symbols as well as rich input
Fix logging FSM wrapper and move logging tests down to the logging test case
Lint fix and topfile