curses erase char and kill char

Support user's terminal settings for erase char and for kill char.
Erase char is typically <delete> or <backspace>, both of which are
already explicitly handled so probably no effect there.  Kill char
(generally ^U these days) will be honored unless it is a printable
character (don't know whether there are any troglodytes out there
who still use '@' for that...).  The current handling for ESC works
the same if there is any input to kill, but yields 'cancelled' when
there isn't.

That's for message window getline(), which operates char-by-char.
The popup getline() uses a curses routine to get an entire string
and already honors kill char but treats ESC as input of ^[.

doc/fixes36.3

@@ -1,4 +1,4 @@
-$NHDT-Branch: NetHack-3.6 $:$NHDT-Revision: 1.71 $ $NHDT-Date: 1561457861 2019/06/25 10:17:41 $
+$NHDT-Branch: NetHack-3.6 $:$NHDT-Revision: 1.72 $ $NHDT-Date: 1561681080 2019/06/28 00:18:00 $
 
 This fixes36.3 file is here to capture information about updates in the 3.6.x
 lineage following the release of 3.6.2 in May 2019. Please note, however,
@@ -156,6 +156,8 @@ curses: when map window was clipped, the 'scrollbars' shown to indicate which
 	"*--------------" for horizontal (and comparable '*' with multiple '|'
 	underneath for vertical) when it meant to show "---******------" if
 	the 2nd and 3rd fifths (for example) were currently within view
+curses: support users's setting for erase char and kill char when getting a
+	line of input with 'popup_dialog' Off (already supported for popup On)
 curses+'perm_invent': entries were wrapping without any control; usually not
 	noticeable because next entry overwrote, but visible for final entry
 	when whole inventory fit within the available height; looked ok with