Resize handler detection should not be active when moving multip… (#767)

* Fix bug.

* Implement `getSelectedElements`.

* Explicit condition.

* Respect variable naming.

* Keep state consistent.

* Use `isSomeElementSelected` abstraction.

* Missing ones.

src/scene/index.ts

@@ -3,9 +3,10 @@ export {
   clearSelection,
   getSelectedIndices,
   deleteSelectedElements,
-  someElementIsSelected,
+  isSomeElementSelected,
   getElementsWithinSelection,
   getCommonAttributeOfSelectedElements,
+  getSelectedElements,
 } from "./selection";
 export {
   exportCanvas,