This fixes the part of pull request #1102 by entrez dealing with the
map refresh side of things. It was pulled out of a much larger patch
that also deals with terminal window resize for tty.
Using ^R when getpos() is in operation, whether actually picking a
position for something or browsing the map during #terrain or post
detection magic, it was reconstructing the known map and positioning
the cursor on the hero instead redrawing the selected terrain subset
or detected objects/monsters/whatever. There's already a routine to
redraw the current view of the map without recalculating it, but it
wasn't being used for ^R during getpos operation.
f70f84aee7