Header Sprites

Well we wanted them, so here there are.

I did them as spans, some may grumble but they can change it as well :wink:  I did them that way as it provided a bit more flexibility due to how the existing ones were used in various locations.  Added a couple of extra ones to the sprite, not many though.  Also added a class option to the generic thingy so you can just call the icon class (well the common name really, not the entire class name).

This helps out on profile summary, stats page, theme page and a few others since there were multiple calls for icons.  In the other areas one could make the argument that this hurts (since we trade a single small icon for a larger sprite, but hey its cached at that point so splitting hairs and in the overall scheme its mo better)

There are a few areas that may still have been using a small icon in the header, this did not change that, but as you find them you can just add a span with the class and be done, no $scripturl no $settings, no img etc, nice and easy.