IE8 Fixes (part 2)

Three small fixes here:

* #434 - CSS tweaks: Adding fallback colors for `rgba`, and swapping `::after` for `:after`
* #435 - Enable CORS support in jQuery
* #430 - Click event handler changes
I don't think jQuery supports CORS on IE8 at all… from what I remember you can provide your own `xhr` factory as part of the request[1] and then return an `XDomainRequest` object[2]. Theres some discussion here[3]. Or alternatively there seems to be a few libraries offering the patch, but they all seem to use dubious methods.

Also I believe the `XDomainRequest` only supports a subset of the full CORS api, no custom headers with POST I think,) so it may not work for us anyway.

[1] http://api.jquery.com/jquery.ajax/
[2] http://msdn.microsoft.com/en-us/library/ie/cc288060(v=vs.85).aspx
[3] http://bugs.jquery.com/ticket/8283