listconf.c: Optimize format list output (--list=formats) for pipes

[magnumripper]

When scripting or writing "oneliners" the commas are just in the way and requires special handling. We now skip them and list one format per line if output is not a terminal.

$ ../run/john -list=formats -form=*crypt
descrypt, bsdicrypt, md5crypt, bcrypt, scrypt, adxcrypt, AxCrypt, BestCrypt, 
sha1crypt, sha256crypt, sha512crypt, django-scrypt, streebog256crypt, 
streebog512crypt, gost94crypt, Raw-SHA1-AxCrypt, sm3crypt, crypt
18 formats

$ ../run/john -list=formats -form=*crypt | wc -l
      18

$ ../run/john -list=formats -form=*crypt | grep ^sha
sha1crypt
sha256crypt
sha512crypt

[solardiz]

I assume you tested this, so don't review the conditions very closely. I'd rename/invert stdout_is_pipe to stdout_is_tty (so also invert its checks later). Not a tty does not imply pipe - it can be various non-tty things.