Send an input to self

[mkawalec]

A pattern I keep on needing in the ability to trigger an action while handling another action in an agent. This adds the ability of sending another input message while handling an input message.

[jstarry]

@mkawalec I'm not super opposed to this change but I'm curious, why not send a message instead? Is it to avoid duplicating code?

[mkawalec]

@jstarry In the Store pattern I have it wired in such a way that Inputs are actions that we want to execute and Messages carry action results to reducers. I would have to make the code a bit awkward and handle 'messages that actually want to trigger actions' in the reducers (thus mixing concerns) instead of cleanly invoking new actions with Inputs.

[jstarry]

Got it, I could see there being awkwardness there