Use getopt-based parser for command-line arguments

Upcoming commits will want to make use of bespoke argument handling
alongside subcommands and using Python's argparse proved unable to
easily handle that kind of complexity. Therefore switch to the more
basic getopt-based parser with which we can implement our own logic.

Without argparse we're no longer bound to having an autogenerated help
listing, so stop mentioning that in the manual. Instead have later(1)
output a concise usage listing when given an unknown argument.

Since we'll be adding more commands to later(1) in the future, also
specify an explicit "list" command.

0 files changed, 0 insertions, 0 deletions