Increased <img> tag dimensions to 20x20 and increased the size of header font in the pop-up to match.  Added an on-hover text-tip to show that the "Fill field" button will only populate empty fields.  Changed == and != to === and !== and used parseInt() where needed for exact equality.
Updated sjcl.js to latest git version and removed the need for rijndael.js since it was only being used in one place for no reason because sjcl.js is both smaller and faster for AES encryption.
Also fixed the Settings.makeKey() function so it actually gets all hex values from 0-f instead of only 0-d.