curses: getline vs DEL, ESC

Support <delete> (aka <rubout>) during getline().  It doesn't actually
honor the current erase_char value set up for the terminal, just
treats DEL the same as ^H.  (The previous lack of support had nothing
to do with terminfo specifying ^H; the handling is hard-coded.)

tty treats escape while there's already some input as kill_char (erase
the input but get more from scratch) and returns ESC if there isn't.
curses was doing the first half but not the second, so not providing
any way to communicate "cancel" back to the core.  Fix is simple.

Other getline() bug fixes:
1] there was a wprintw("%*something") which was passing the value from
strlen (type 'size_t') to the "%*" argument (type 'int').  That's
always wrong (size_t is guaranteed to be unsigned) and could be severe
(if size_t is different width than int--as on current OSX systems--
depending upon the internals of argument passing).
2] strncpy() only supplies a terminating '\0' if the input is shorter
than the number of characters specified.

A lot of reformatting is warranted but I only did the getline routine
(manually, so might have missed stuff).

doc/fixes36.2

@@ -1,4 +1,4 @@
-$NHDT-Branch: NetHack-3.6.2-beta01 $:$NHDT-Revision: 1.251 $ $NHDT-Date: 1549586901 2019/02/08 00:48:21 $
+$NHDT-Branch: NetHack-3.6.2-beta01 $:$NHDT-Revision: 1.252 $ $NHDT-Date: 1549666475 2019/02/08 22:54:35 $
 
 This fixes36.2 file is here to capture information about updates in the 3.6.x
 lineage following the release of 3.6.1 in April 2018. Please note, however,
@@ -442,6 +442,9 @@ curses: catch up with tty to not put dolook/whatis autodescribe feedback into
 curses: if the interface code ran out of memory, it would crash rather than
 	attempt a controlled panic (which is fairly likely crash anyway if
 	done when there's no memory available)
+curses: when getting multi-character responses from player, support <delete>
+	as well as <backspace> to remove last character entered; also, return
+	<escape> to core if ESC is typed when there is no input entered
 
 
 Platform- and/or Interface-Specific Fixes or Features