Find and manage duplicate files

Issues

#	State	Title
16	OPEN	Filter dupes safely by default (never return every entry in a list)
15	CLOSED	Dupe scanning fails for files > 1K!
14	OPEN	Show dupe-scanning progress
13	OPEN	Rescan a set of file-hashes
12	OPEN	Scan multiple sets of file-hashes for dupes
11	OPEN	Scan a set of file-hashes for dupes
10	OPEN	Write out a set of file hashes
9	CLOSED	Rescan an input set of dupes
8	CLOSED	Filter dupes by regex
7	CLOSED	Filter dupes by string matching
6	CLOSED	Replace use of find_duplicate_files PyPI module
5	CLOSED	Write found duplicates to a CSV file
4	CLOSED	Load duplicates file for processing
3	CLOSED	Write found duplicates to a file
2	CLOSED	List duplicates in multiple directories
1	CLOSED	List duplicate files in a single directory