Changed the semantics of the Convolution filter a bit. It now doesn't try
to normalize the filter values but leaves this to the client. This
gives more reasonable behaviour in the limit where the filter
parameters sum up to 0.
change "foo.h" to <X11/foo.h> for core headers, e.g. X.h, Xpoll.h;
change "foo.h", "extensions/foo.h" and "X11/foo.h" to
<X11/extensions/foo.h> for extension headers, e.g. Xv.h;
change "foo.[ch]" to <X11/Xtrans/foo.[ch]> for Xtrans files.