Bulk select (#395)

* add rect for select

* collect selected elements

* increase note stroke width

* move elements and undo redo

* add icon to toolbar to toggle multiselect mode

* set bulk selected elements to none when panning

src/i18n/locales/en.js

@@ -247,6 +247,8 @@ const en = {
     show_relationship_labels: "Show relationship labels",
     docs: "Docs",
     supported_types: "Supported file types:",
+    bulk_update: "Bulk update",
+    multiselect: "Multiselect",
   },
 };