When scrolls of magic mapping or gold detection were read, their
characteristic messages were displayed before overwriting the whole
screen to show the newly discovered information. They are now shown
after updating the screen, so they will be visible.
new_level() redraws the whole screen, including the message line, so if
msg() has just been called, the message will likely not last long
enough to be noticed. These cases have been changed so that msg() is
called after new_level().
If a fall through a trapdoor is fatal, "You fall into a trap!" is no
longer printed, but the tombstone should make things clear.
