Allow MiradorViewer to accept additional configuration (like a store)

src/init.js

@@ -3,6 +3,14 @@ import MiradorViewer from './lib/MiradorViewer';
 /**
  * Default Mirador instantiation
  */
-export default function (config, plugins) {
-  return new MiradorViewer(config, plugins);
+export default function (config, pluginsOrStruct) {
+  let struct;
+
+  if (Array.isArray(pluginsOrStruct)) {
+    struct = { plugins: pluginsOrStruct };
+  } else {
+    struct = pluginsOrStruct;
+  }
+
+  return new MiradorViewer(config, struct);
 }

src/lib/MiradorViewer.js

@@ -15,10 +15,12 @@ import { getCompanionWindowIdsForPosition, getManifestSearchService } from '../s
 class MiradorViewer {
   /**
    */
-  constructor(config, plugins) {
-    this.store = createStore();
+  constructor(config, viewerConfig = {}) {
     this.config = config;
+    this.plugins = viewerConfig.plugins || [];
+    this.store = viewerConfig.store || createStore();
     this.processConfig();
+
     const viewer = {
       actions,
       store: this.store,
@@ -26,7 +28,7 @@ class MiradorViewer {
 
     ReactDOM.render(
       <Provider store={this.store}>
-        <PluginProvider plugins={plugins} createRootReducer={createRootReducer}>
+        <PluginProvider plugins={this.plugins} createRootReducer={createRootReducer}>
           <App />
         </PluginProvider>
       </Provider>,