the colon in timezone is optional per ISO 8601

I can't link to an official ISO-8601 document, but meh, [wikipedia article says so](http://en.wikipedia.org/wiki/ISO_8601#Time_zone_designators), and Chrome 31 and FF 25 are forgiving about it, but this if there isn't a colon in the timezine i.e: `+0000` it fails in Safari 7: 

```
var d = "2013-11-11T00:00:00.000+0000";
var d1 = "2013-11-11T00:00:00.000+00:00"
// pre regex change
Date.parse(d); // returns NaN in Safari, but works in Chrome and FF
Date.parse(d1); // works in all 3 browsers and IE8

// post regex change
Date.parse(d); // works in all 4 browsers mentioned above
```
All manual tests on a Mac OS X 10.8

Thanks