Nitpicking many pages on developer.gnome.org: patch

[Aaron Weber <aaron ximian com>]

I sent this earlier with the patch attached, but it was rejected because
the patch was too big... so I've posted the patch here:

http://primates.ximian.com/~aaron/new-devel-diff.diff
Ex_seb and I went through developer.gnome.org today and fixed a bunch of
tiny things in a number of pages-- fixing links, a few typos, and the
"Last changed" dates on a few pages as well.

We found a few issues we weren't sure what to do about, but the minor
issues we figured could be resolved without too much discussion. 

Also, I revised some of the phrasing in the window management
description, and updated information on the GDP pages that sad "SGML" or
Custom Stylesheet" since those are obsolete now.

What say ye?

a.