Javadoc.
Introduce MinimalContext, making that available for injection.

This works around the awkwardness of having multiple points of flow control and response access.
Reinstate reloading of action chains.
Javadoc.
Remove unused method.
Remove an init variant, and add some Javadoc.
Make some classes internal, and minor tweaks to the Groovy version check.
Test fixes.
Doc link fixes.
Upgrade to latest Netty version