Use new sprites.

I bumped the old icons up a few pixels for css-sprite-pokemon-icons.png
because they looked weird being out of alignment with the new ones in
breeding compatibility.  That's the only place they're arranged
horizontally and there won't be any alt-forms in there so I don't care
about hacking together a solution for alt forms.

The CSS is a little messy.  Sorry.  I didn't feel like figruing out
anything cleaner for the sake of spline-pokedex at the end of its life.

Likewise, I should probably have dealt with female Meowstic's icon by
checking whether it exists instead of special-casing it but whatever.