Handles multiple items with the same (#57)

* Handles multiple items with the same

* Refactor multiple items with same id handling

cosmoz-data-nav.js

@@ -403,15 +403,19 @@
 		 * @return {void}
 		 */
 		setItemById(id, item) {
-			const index = this.items
-				.findIndex(item => this._getItemId(item) === id);
+			const items = this.items,
+				matches = items.filter(item => this._getItemId(item) === id);
 
-			if (index < 0) {
+			if (matches.length === 0) {
 				console.warn('trying to replace an item that is not in the list', id, item);
 				return;
+			} else if (matches.length > 1) {
+				console.warn('found multiple items with same id');
 			}
 
-			this.set(['items', index], this._cache[id] = item);
+			this._cache[id] = Object.assign({}, item);
+			matches.forEach(match => this.set(['items', items.indexOf(match)], Object.assign({}, item)));
+
 			this._preload();
 
 			if (this.animating || this.selected == null) {