Update the bundled jQuery to version 1.11.0

The version of jQuery that is currently bundled with Dancer, as well as the one retrieved from a CDN, is 1.4.2, which is horribly outdated (released in early 2010). Even though we're not doing much with it in the skeleton app (only using it to toggle the "About your application's environment" box), we better replace it with a recent version.