WISHLIST:
	findimagedupes should be parallelizable
	https://bugs.launchpad.net/ubuntu/+source/findimagedupes/+bug/502224

	use sqlite to store db

	prevent db corruption on abort (sqlite transaction?)

	implement phash fingerprints

	implement pixel-exact matching (eg. images differing only by exif data; images stored in different lossless formats)

	benchmark against naive use of gcc's _builtin_popcountll

	handle HEIC image format


DOCUMENT:

	add pointers to other image-comparison programs

	warn about false positives

	warn that fingerprint may change if graphicsmagick version changes

	note that database has to fit in ram

BUGS:

	find/fix memory leak

