Plug for reloading modules on every request, allowing fast iteration during development.

Reloading only happens in dev, every other environment is a noop for this plug. If a module is reloaded, a redirect is sent to the client for the same location, allowing the whole plug pipeline to be used with the new code. All further processing on the original request is halted.

Modified from https://github.com/sugar-framework/plugs/blob/master/lib/sugar/plugs/hot_code_reload.ex