Devcards support hot code reload loses state

[awkay]

Need to change the macro to do something more like in the om next helpers:

bhauman/devcards@234a91d

[awkay]

This is a relatively easy fix. The following code will work as long as the cards don't share the same root UI node:

(defmacro untangled-app
  "Embed an untangled client application in a devcard. The `args` can be any args you'd
  normally pass to `new-untangled-client` except for `:initial-state` (which is taken from
  InitialAppState or the card's data in that preferred order)"
  [root-ui & args]
  (let [s (symbol (str (name root-ui) "-application"))]
    `(devcards.core/dom-node
       (fn [state-atom# node#]
         (defonce ~s (atom (untangled.client.core/new-untangled-client :initial-state state-atom# ~@args)))
         (reset! ~s (untangled.client.core/mount (deref ~s) ~root-ui node#))
         ; ensures shows app state immediately if you're using inspect data and InitialAppState:
         (js/setTimeout (fn [] (swap! state-atom# assoc :ui/react-key (untangled.client.util/unique-key))) 1000)))))

If we wrap that in a defuntangled-card macro we can leverage the unique symbol there to fix this.