Add a --classic flag about lsd

[Peltoche]

The --no-icons is already planned with the same logic than --color (#69) and it can solve most of the usecases.

Based on my experience I think the --classic could useful because most of the time when I pipe ls I use less behind for the pagination (ls --tree | less for example). With the default --color (and soon the default --icon) flag value to auto I loose the colors (and soon icons). In order to solve this my alias looks like alias ls='lsd --color=always --icon=always and my less output is pretty again.

This solution works fine with most of my daily needs but sometimes I want to use the ls output for other stuff than less. In those few cases I am currently blocked by my alias. It's in this case that the --classic can help. By explicitly use this flag (ls --classic | xargs rm) I override temporary all my configurations set into my alias and remove all the icons and the colors in order to make xargs usable.

[mitnk]

--classic may not needed explicitly to users. When lsd is found being redirected into pipes, it should make itself remove colors, hide icons, etc. (just like classic ls do with --color=auto).

[mitnk]

Just for curiosity, in what situation you need always, while auto doesn't do the job?