@Fhocutt ran into a lot of problems.
API:Extension needs work
- explain prefix
- explain tokens better
- update example
- big new section about returning API errors and warnings "How $ApiStatus and ApiBase::dieStatus() work, and API error handling on the server side in general."
- synchronize the example code with extensions/examples/Example and new extensions/BoilerPlate
- update the i18n message stuff.