Allow customization of generated py_ext OnChange calls, by adding a static method to PythonFileCTNMixin that can the be later hot patched.
#!/bin/bash
INKSCAPE=inkscape
for i in `cat icons.svg |grep -o -e '%%[^%]*%%'|sed 's/%//g'`
do
if [ $i.png -nt icons.svg ]; then
echo "Skip $i"
else
rm -f $i.png
echo "$INKSCAPE" icons.svg -z -e $i.png -i $i
"$INKSCAPE" icons.svg -z -e $i.png -i $i
fi
done