We already redirect all terminal output through our own wrappers (for
the sake of UTF-8), so we might as well use it to handle ANSI escape
codes.
This also changes behavior on UNIX: we don't retrieve some escape codes
per terminfo anymore, and just hardcode them. Every terminal should
understand them.
The advantage is that we can pretend to have a real terminal in the
normal player code, and Windows atrocities are locked away in glue
code.