maybe fix #H5264 - screen clears on prompting

I couldn't reproduce the reported problem of the "In what direction?"
being issued after the screen was cleared, but bypassing pline() in
favor of putstr(WIN_MESSAGE) for tty prompts did also bypass
  if (vision_full_recalc) vision_recalc(0);
  if (u.ux) flush_screen(1);
done in pline().  Inadvertent loss of the latter could conceivably be
responsible for the problem.  If so, the escape code used by cl_end()
may be broken for somebody's termcap or terminfo setup since clearing
to the end of the line in the message window shouldn't erase the rest
of the screen.

Regardless, the prompting change also bypassed the ability to show
the prompt with raw_printf() if the display wasn't fully intialized
yet, so some change to the revised prompting was necessary anyway.

Switching back from putstr(WIN_MESSAGE) to pline() resulted in
duplicated entries in DUMPLOG message history, one with bare prompt
followed by another with response appended, so more tweaking was
needed.  The result is use of new custompline() instead of normal
pline().  custompline() accepts some message handling flags to give
more control over pline()'s behavior.  It's a more general variation
of Norep() but its caller needs to specify an extra argument.

doc/fixes36.1

@@ -402,6 +402,7 @@ DUMPLOG: RIP tombstone was printed for characters who survived (ascended,
 	escaped dungeon, quit, trickery or panic)
 artifact creation violated illiterate conduct when artifact name was assigned,
 	behavior intended only for creating Sting or Orcrist via naming
+tty: revert to pline() for issuing prompts (override MSGTYPE=hide differently)
 
 
 Platform- and/or Interface-Specific Fixes