fix #676 bump dependencies

Build was failing due to jshint / contrib-jshint incompatibility.
fix #678 Work-around for scrollbars not removed correctly on Chrome.

Adds an aria.utils.Dom.refreshScrollbars method as a work-around
for Chrome bug http://crbug.com/240772 : scrollbars are not removed
when they are no longer necessary if the content has nearly the same
size as the container.