manually changed the pHash source code to support alpha channel PNGS
IE, made this change,
https://github.com/westonplatter/phash/commit/ff255d2d3f93c841b98923ecbde997027f21ae36
added tests for PNG fingerprints
https://github.com/mperham/phashion/issues/20 rename pHash zip for clarity
Merge pull request #23 from westonplatter/temp-png-fix

fixes #20 patch pHash to support alpha channel PNGs