#27 Math exception crash

[Christopher Morris]

Waimea was causing a math exception (divide by zero) in
Image.cc in WaImage::xrender(). A diff containing the
fix for the CVS version is attached.

How to fix for 0.4.0:
In WaImageControl::xrender:
change:
if (w < (unsigned int) wascreen->width ||
h < (unsigned int) wascreen->height) {

to:
if (w != 0 && h != 0 &&
(w < (unsigned int) wascreen->width ||
h < (unsigned int) wascreen->height)) {

(note the extra parens, that got me the first time I
tried to fix it :-) )

[Christopher Morris]

Diff with crash fix