This is a stopgap while I figure out how I should go about implementing
vis(3). It's also important to have some vis(3) implementation so I can
do integration tests on round-trips.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Also add some unit tests -- one of which currently fails due to ongoing
design discussion about how certain escape codes should be handled.
Signed-off-by: Aleksa Sarai <asarai@suse.de>