Updated jQuery to v2.1.0 & a bunch of hopefully good stuff like issue #94 & #87

Updated jQuery to v2.1.0, removed need for jQuery-UI, updated sjcl.js to latest version.
Updated .bind's to .on's.
Used vanilla JS in content.js so no need to include jQuery into "content_scripts" in manifest.json.
Fixed response.hasField bug which crashed when no password field exists.
Fixed the issue I reported (#94).
Also addresses Issue #87; feel free to revert this change and make it so that all password fields get overwritten if you prefer though...
Removed onclick() handlers from popup.html, goes against security policy & they were duplicated event handlers.
General code maintenance and formatting.