Improve the entire icon logic

- Tree Shaking for Icons (Closes #53)
- New API for the config (See 
https://github.com/uwap/mqtt-control-map/wiki/Icons)
- Icons can now be colored everywhere, not just on the map

src/components/App.js

@@ -39,6 +39,14 @@ export type AppState = {
   error: ?string
 };
 
+/*
+const App = (props: AppProps) => {
+  const topics = Array.isArray(props.config.topics) ?
+      Object.assign({}, ...props.config.topics) : props.config.topics;
+  const [mqttConnected, setMqttConnected] = useState(false);
+};
+*/
+
 class App extends React.PureComponent<AppProps & Classes, AppState> {
   controlMap: React.Node
 
@@ -171,7 +179,7 @@ class App extends React.PureComponent<AppProps & Classes, AppState> {
           control={this.state.selectedControl}
           onCloseRequest={this.closeDrawer}
           icon={this.state.selectedControl == null ? null :
-            this.state.selectedControl.icon(this.state.mqttState)}
+            this.state.selectedControl.icon.render(this.state.mqttState)}
         >
           {this.state.selectedControl == null
             || <UiItemList controls={this.state.selectedControl.ui} />}