Support for hot reload

[beders]

First of all: Bide just works! It's great. Thank you!

I'm using shadow-cljs and that means frequent reloads of code.
However, I have to stuck any bide setup code in init (i.e. it only runs once), since it seems there's no stop! method and setting up another router leads to multiple registration of navigation events (i.e. after 4 re-loads any click on a route is done 4 times).

Would be great to have a stop! function to cleanup or a way to dynamically add routes.