Upgrade embedded version of jquery.tablesorter.js to 2.0

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.
Merge pull request #93 from storborg/master

Fix for intermittent jquery.tablesorter.js loading issues