Use :not() CSS pseudo-class instead of jQuery .not() filter in selector

The old version would iterate over all links on the page (try that on
[[Barack Obama]]), the new one should be optimized by the browser and
poly-filled by jQuery if unavailable.

We can't do `:not(.extiw, .image, .new, .internal, [title=""])` –
while some browsers support it, CSS specification doesn't allow
compount selectors inside :not().

Change-Id: I0e4b18752905604ebf1b7f41a9b7ac2edd8b42e0