Added JS engine colour stripe to platform headers.

Now, platforms' table <th> elements have a thin colour strip denoting their engine. Colours have been set for Trident (IE), SpiderMonkey (Firefox/Rhino), JavaScriptCore (Safari, Phantom, WebKit), V8 (Chrome, Opera, Node), Carakan (Opera 12) and KJS (Konqueror). This allows browsers versions to be more easily visually identified, as well as providing context to e.g. the similarity of WebKit and iOS.
Fixed bugs in Safari 7.1 commit

* The colspan of the "desktop" platform column wasn't updated.
* Added Map, Set, WeakMap and destructuring notes to Safari 7.1's
results.
Forgot to update master.js, too
Converted master.js to jQuery

All features are preserved, though some may call for optimisation.

ready.js is now no longer needed.

Also, feature totals are now coloured from red to green denoting how
many are implemented.
Merge pull request #270 from webbedspace/webkit

Fixed bugs in Safari 7.1 commit
Fixed sorting and column hovering.

Also added a visual garnish: platform header cells now have a 'bar graph' gradient background corresponding to their feature total.
Used .css() instead of making a <style> element.
Merge pull request #268 from webbedspace/css

Added JS engine colour stripe to platform headers.
Merge pull request #271 from webbedspace/jquery

Converted master.js to jQuery
Fixed undeclared var, and added 'use strict' to master.js