Cleanup to the PHP side of things.

* Swapped $IP to $wgStylePath and declared it as a global; $IP is the _internal_ include path, you don't want to be using that for things like image paths
* Swapped $wgUser to $wgUser->getName() -- $wgUser is a *global object*, not a string
* Commented out one empty <img> tag, no idea what it was being used for, if anything
* Added an empty alt attribute to all <img> tags -- W3C Validator expects that to be present and if it's not, then the page will fail validation. Silly but true.
* Added dataAfterContent (though it's not like there are too many extensions using it, but hey, consistency is good)
* Tweaked search bar code -- now it supports search suggestions out-of-the-box