implement slice

www/common/cryptpad-common.js

@@ -103,6 +103,7 @@ define([
     common.getAppType = Util.getAppType;
     common.notAgainForAnother = Util.notAgainForAnother;
     common.uid = Util.uid;
+    common.slice = Util.slice;
 
     // import hash utilities for export
     var createRandomHash = common.createRandomHash = Hash.createRandomHash;