Postscript file generates AprilTags with black and white reversed

[cynosure4sure]

I saw a recent commit which corrected png files as they had black/white bits reversed. I think the provided postscript files still generate tags with black/white bits reversed.

The postscript files from commit 8314470 have the correct order of bits for tag generation.

[mkrogius]

Fixed in #64a553eeb9872944abfd4ad9258a644aded973fa

Thanks