Update benchmarks and add czkawka and rmlint to comparsion about fclones

[pkolaczk]

Very quick one time comparison on my home folder (SSD).
Cold cache:
czkawka: 1:34.47
fclones 0:47.291

Hot cache (2nd run):
czkawka: 1:21.78
fclones: 0:18.996

Things I noticed:

1. czkawka has found fewer duplicates than fclones (~330k vs 372k). I did set the minimum size to 0 in czkawka to match fclones settings.
2. czkawka uses 100% of one core after displaying the results in the window

[pkolaczk]

After removing "excluded items", the timing of czkawka got worse: 1:52.83

BTW: Where does czkawka store the hash cache?
I wonder if the fact that I've already run it before hasn't messed up the timings.

[qarmin]

~/.cache/czkawka - should contains cache from different types of tools

Also by default on Linux Czkawka don't show hardlinked files as duplicates(this can be disabled in settings)

[pkolaczk]

Also by default on Linux Czkawka don't show hardlinked files as duplicates(this can be disabled in settings)

That's the same for fclones, unless option -H is given.

[pkolaczk]

Done as part of #56