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
@nickstenning Ok, since jQuery isn't properly handling IE's native XDomainRequest method, we'll need to add [something like this to patch it](https://github.com/MoonScript/jQuery-ajaxTransport-XDomainRequest).