Listener middleware fires for all Messages, not just TextMessages

[technicalpickles]

Keep in mind that listener middleware fires for every listener type, not just ones from robot.hear and robot.respond. `robot.

Those aren't "commands" per se, so you probably only want to reply on text messages. You can check for the presence of context.response.message.text or if context.response.message instanceof TextMessage.

[kristenmills]

Ah yeah. I'll change that.