Execute Bot#configure in the Callback instance

[dominikh]

We used to do this and not doing it breaks instance variable initialization for on handlers.

[causal-agent]

:+1:

Workarounds for now?

[dominikh]

Use the plugin architecture instead of plain on handlers. The latter were always supposed for very basic things, not necessarily things that have state.

[dominikh]

This cannot be fixed before Cinch 3.0, because changing it breaks backwards compatibility.