Allow reverse flag for sorting by name

[rheber]

#73

[foolip]

I have merged and tested this change locally and confirmed it to work. Thanks!

[jfilak]

Could you please merged this pull request? I spent an hour debugging until I noticed that the flag --reverse works only for the time based sorting.

Well, IMHO multiplying by -1 is not the most obvious way how to do that but it sure works.

[jfilak]

@jbruchon Thank you very much. Since I already had the sources on my machine, I did my version of the patch:
return !ISFLAG(flags, F_REVERSE) ? strcmp(f1->d_name, f2->d_name) : strcmp(f2->d_name, f1->d_name);

built it, removed the correct files and dropped the local build :)

[FabioPedretti]

Duplicate of #102?