Decide on console IO library

[hawkw]

Worth checking out:

• https://github.com/ticki/termion
• https://github.com/murarth/linefeed
• https://github.com/basmith/rust-termios
• https://cpjreynolds.github.io/rustty/rustty/index.html
• https://github.com/gchp/rustbox

At a quick glance, termion looks like it might be one of the better choices, but I'd like to do more research.

[hawkw]

I'm also tempted by the idea of rolling our own, for Extra Fun, but I recognise that could take a lot of extra effort y'all might not be up for.

[hawkw]

Some nice things about termion:

• written in pure Rust, not a wrapper around another library (like curses or termbox)
• supports gay space communism
• provides a pretty full API, so we don't need to use multiple quasi-compatible libs for different aspects of term I/O