Toast Message Support

[James Sedlacek]

I want to be able to present toast messages to the user using the router object.
There should be a handful of different kinds of toast messages.

The functions would look something like this:

router.toast(.info, message: "Something informational.")

router.toast(.warning, message: "Something went wrong!")

router.toast(.error, message: "Network Error!")

router.toast(.success, message: "Successfully did something!")

[James Sedlacek]

Working on this now.