Integrate Audioglider's Fragment tool

Many thanks to Audioglider for helping us fill in another missing
Photoshop filter.  Very clean and elegant implementation.  (And how
great is the filter message?? lol)

My only change is extra handling for the alpha channel in 32bpp layers.

Also included in this commit is a reworking of the Effects -> Blur menu,
not just to add the new Fragment tool, but to sort blurs by type
(generic, directional, misc).  Also I have renamed "Smart Blur" to
"Surface Blur" to match Photoshop's convention.