Fix for intermittent jquery.tablesorter.js loading issues

Refs #73. Fixes a timing error which causes intermittent failures in some browsers (Chrome, Safari). When it occurs, the particular failure prevents the console and source icons from working on a debugger page, and prevents the sidebar from showing up at all.

Simply upgrades the embedded version of ``jquery.tablesorter.js`` to 2.0, which doesn't have the issue.