Use lua for special level files

Game is playable, and should compile on linux and Windows.
Assumes you have a lua 5.3 library available.

Removes level compiler and associated files.
Replaces special level des-files with lua scripts.
Exposes some NetHack internals to lua:
 - des-table with commands to create special levels
 - nh-table with NetHack core commands
 - nhc-table with some constants
 - u-table with some player-specific data (u-struct)
 - selection userdata

Adds some rudimentary tests.

Adds new extended command #wizloadlua to run a specific script,
and #wizloaddes to run a specific level-creation script.

nhlib.lua is loaded for every lua script.

Download and untar lua:
  mkdir lib
  cd lib
  curl -R -O http://www.lua.org/ftp/lua-5.3.5.tar.gz
  tar zxf lua-5.3.5.tar.gz

Then make nethack normally.

dat/minefill.lua

@@ -0,0 +1,50 @@
+-- NetHack 3.6	mines.des	$NHDT-Date: 1432512783 2015/05/25 00:13:03 $  $NHDT-Branch: master $:$NHDT-Revision: 1.25 $
+--	Copyright (c) 1989-95 by Jean-Christophe Collet
+--	Copyright (c) 1991-95 by M. Stephenson
+-- NetHack may be freely redistributed.  See license for details.
+--
+--
+
+--	The "fill" level for the mines.
+--
+--	This level is used to fill out any levels not occupied by
+--	specific levels.
+--
+des.level_init({ style = "solidfill", fg = " " });
+
+des.level_flags("mazelevel");
+
+des.level_init({ style="mines", fg=".", bg=" ", smoothed=true ,joined=true, lit="random", walled=true })
+
+--
+des.stair("up")
+des.stair("down")
+--
+des.object("*")
+des.object("*")
+des.object("*")
+des.object("(")
+des.object()
+des.object()
+des.object()
+--
+des.monster("gnome")
+des.monster("gnome")
+des.monster("gnome")
+des.monster("gnome")
+des.monster("gnome")
+des.monster("gnome")
+des.monster("gnome")
+des.monster("gnome lord")
+des.monster("dwarf")
+des.monster("dwarf")
+des.monster("G")
+des.monster("G")
+des.monster("h")
+--
+des.trap()
+des.trap()
+des.trap()
+des.trap()
+des.trap()
+des.trap()