update package hideshow.el

I initially took a look at synching our hideshow with the one in 20.5. It is somewhat a pain in the ass as the newer hideshow has switched to using overlays vs selective-display which our current version uses. I suspect, but am not positive, that this switch was done to make things work under MULE and/or NT.

Now, I suspect the sticky point with this version will be that it uses the overlay package, which is considered just a compatibility package. But I don't see any clean way around this. either he comes up with some kludgey way to handle both extents and overlay or he uses our kludgey way to handle them. It just seem a better choice to go with the actively maintained version. As Thien-Thi mentioned in an earlier message to the xemacs mailing list, it might be more appropriate for this version to be in something like the prog-modes package, since it will work for more than just c code. It will work for java, lisp, etc. Thien-Thi: If the reviewers accept this version of hideshow, then please send future patches, etc. to xemacs-beta(a)xemacs.org.