'Edit Shortcut' panel redesign [UX]

As per #1196

CSS and HTML changes only. Tested in Firefox & Chrome, don't know how to test in IE.

**I need your help to finish this.** I tried writing some JS to switch the A-Z label to Z-A (and the title attribute to "reverse-alphabetical") depending on the current sorting method, but it's beyond my level. If one of you programmers could offer some code or guidance then I can get it finished.

Working Screenshot:
![res-edit-shortcut-proof-01](https://cloud.githubusercontent.com/assets/7245595/3208892/4ba92094-ee4b-11e3-8343-a1a3bc8259ff.png)