Handlers don't work / are stubbed.

[johrstrom]

Handlers don't currently work because they're are stubbed, or the code simply hasn't been written for it. This ticket is to write the functionality for them. Some context will have to originate with event nodes (i.e., they failed, or succeeded and reasons why) and be passed to the appropriate handlers.

This ticket is only to implement the plumbing for passing this context, it does not include the implementation of any given type of handler.