From a bug report, attempting to respond with ESC when playing an instrument
just continued with the playing sequence. This adds a q choice to the
"Improvise? [yn]" and "Play passtune? [yn]" prompts, and also checks
for ESC as the 5-note tune when not improvising, yielding "Never mind"
and not using up a turn if the player opts not to play any music.
I put the fixes entry in the new features section since the old
behavior wasn't much of a bug.