Add subscribe decorator for use with event handlers.  Revise events documentation.
Add tests for subscribe decorator.
Fix wrong and add missing API docs.
Merge pull request #217 from disko/feature/event_subscription

Feature/event subscription
Revise events docs.  [ci skip]
Fix doc issues.
Add a *simple* MANIFEST.in to make RTD happy again.
Make validators happy on master templates.
Added well well-small class to divs containing slots. Added .well:first-of-type CSS to slot containers (thanks @disko).
Merge pull request #220 from geojeff/slot_wrapping

Added well well-small class to divs containing slots. Added .well:first-...
Add documentation on Kotti's startup phase.
Merge pull request #221 from disko/feature/startup_docs

Add documentation on Kotti's startup phase.