Write command-line help.

[jsbackus]

[jsbackus]

Way to beautify output? Perhaps optionally use lua-term to get terminal size?

[jsbackus]

For *NIX systems, try to execute one of the following:

• tput cols - returns number of columns
• stty size - returns rows x columns

[jsbackus]

For non-POSIX environments, default to 80 cols or whatever "command prompt" defaults to? I don't think it can be resized, so that should work.