Updated installation instructions

[Owen Taylor <otaylor redhat com>]

I spent some time today working on the "Building GTK+" section of
the GTK+ reference manual:

 http://developer.gnome.org/doc/API/2.0/gtk/gtk-building.html

The intent was to make it a fairly complete guide to building
the entire set of 4 GTK+ libraries, covering:

 - A rough guide to the basics of building autoconf'ed packages
 - All the dependencies you need
 - The order to build the libraries in
 - What to do if things don't work.

I'd like to link to this from the GTK+ release announcements,
so I'd appreciate if people would

 - Check it over for completeness
 - Find stupid mistakes
 - Give suggestions for improvements in organization, etc.

Ideas on improving the docbook markup would also be appreciated.

(Within the context of the gtk-doc stylesheets.. taming the 4 color
navigation bar is probably about as much work as I'll have time to do
on the stylesheets. It's rather unfortunate that we don't have any
good way of limiting page width, since extended text like this is
pretty hard to read.)

Thanks,
                                        Owen