many changes (kfftools sort, kfftools shuffle)

[rchikhi]

major:

• kfftools sort
• kfftools shuffle

minor:

• added .kff suffix in instr output prefix,
• input validation
• a small example

[yoann-dufresne]

@rchikhi : I'm not sure about the addition of .kff at the end of the file names. The unix way is that the user enters the full filename on command line. Maybe only when there is no extension specified ?

[natir]

I have more or less the same opinion as @yoann-dufresne if the user has not put an extension it's because he doesn't want it, adding an extension automatically could go against the will of the user

[rchikhi]

fine with me but it was in accordance with how the cmdline instructions were:

CLI::Option * output_option = subapp->add_option("-o, --outprefix", output_filename, "The kff output file prefix. For a single file the name will be <prefix>.kff, otherwise, one file per minimizer is created (<prefix>_<minimizer>.kff).");

it was called a "prefix", but the code didn't add ".kff" at the end as stated.

[yoann-dufresne]

You are right. It is changed on dev since a few days