Update optipng to 0.1.0.
Update optipng to 0.1.1.
Update pngcrush to 0.1.0.
Update pngquant to 0.2.0.
Unbreak targetContentType when inkscape is involved.

It came out as "image/undefined" after 2429db1e.
1.0.2
Fixed pngcrush test so it doesn't break with the pngcrush that came with my Ubuntu.
WIP: avconv support.