v7 utils to port

[bobbimanners]

• nl
• expr (needs yacc)
• yacc
• rm
• mv - this one may be not be feasible because GSOS files have multiple forks
• bc and/or dc
• tar
• cpio

[bobbimanners]

Also hexdump (from Linux text-utils). https://github.com/karelzak/util-linux/tree/master/text-utils

[bobbimanners]

Wrote a simple version of nl from scratch, as it is not included in UNIX v7.