Investigate the feature sets and performance of competing tools

[ssokolow]

First and most importantly, I'll want to investigate rmlint since a brief examination of the README suggests that it's doing the same kinds of optimizations I'm doing but has had a lot more effort put into it.

Depending on how much faster rmlint is, I'll probably want to focus more on the extensibility and hackability I gain from using Python as opposed to C.

Second, I'll also want to investigate schweikh3.c and samefile:

   <mauke> feature request: if you could make it output compatible with
   http://www.ioccc.org/1998/schweikh3.hint , that would be sweet
   (http://www.ioccc.org/1998/schweikh3.c)

    <mauke> I don't like the way fdupes works. samefile's interface is superior
    <mauke> it says if you specify a directory twice, it will list files as
            their own duplicates.
    <mauke> wtf was the author thinking?
    <deitarion> mauke: Lazy, I guess. I believe I fixed that in fastdupes.