fix(IE): Fix selection api on IE (#292)

See react-grid-layout/react-grid-layout#633

Author: STRML

lib/utils/domFns.js

@@ -150,7 +150,12 @@ export function addUserSelectStyles(doc: ?Document) {
 export function removeUserSelectStyles(doc: ?Document) {
   try {
     if (doc && doc.body) removeClassName(doc.body, 'react-draggable-transparent-selection');
-    window.getSelection().removeAllRanges();  // remove selection caused by scroll
+    if (doc.selection) {
+      // $FlowIgnore: IE
+      doc.selection.empty();
+    } else {
+      window.getSelection().removeAllRanges();  // remove selection caused by scroll
+    }
   } catch (e) {
     // probably IE
   }