Compatibility fix

Use ````$(document.body)```` everywhere instead of ````$('body')```` because the latter will select ````<body>```` elements within SVG ````<foreignobject>```` elements, which is never what you want.

Hand picked from https://github.com/kamens/gae_mini_profiler/pull/60
Updated jQuery and changed it to protocol relative URL

Hand-picked from https://github.com/kamens/gae_mini_profiler/pull/50