arogue5: fix player's typed responses getting put at the wrong place.

Some sections of code that prompt the user for a string of input were
calling get_str() with cw (the player-visible screen containing the
map), which caused whatever the player typed to get printed starting at
cw's idea of the cursor position, which was usually the Rogue's @-sign.
This corrupted the map.

The problem has been fixed by passing msgw (the message line at the top
of the screen) to get_str(), so the player's typing appears where msgw
thinks the cursor should be, which is in the sensible place right after
the prompt.  Some other get_str() invocations which used hw or stdscr
have been left unmodified.

arogue5/save.c

@@ -69,7 +69,7 @@ save_game()
 	msg("File name: ");
 	mpos = 0;
 	buf[0] = '\0';
-	if (get_str(buf, cw) == QUIT)
+	if (get_str(buf, msgw) == QUIT)
 	{
 	    msg("");
 	    return FALSE;