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/tower1.lua

@@ -0,0 +1,62 @@
+-- NetHack 3.6	tower.des	$NHDT-Date: 1432512784 2015/05/25 00:13:04 $  $NHDT-Branch: master $:$NHDT-Revision: 1.9 $
+--	Copyright (c) 1989 by Jean-Christophe Collet
+-- NetHack may be freely redistributed.  See license for details.
+--
+--
+-- Upper stage of Vlad's tower
+des.level_init({ style = "solidfill", fg = " " });
+
+des.level_flags("mazelevel", "noteleport", "hardfloor", "solidify")
+des.map({ halign = "half-left", valign = "center", map = [[
+  --- --- ---  
+  |.| |.| |.|  
+---S---S---S---
+|.......+.+...|
+---+-----.-----
+  |...\.|.+.|  
+---+-----.-----
+|.......+.+...|
+---S---S---S---
+  |.| |.| |.|  
+  --- --- ---  
+]] });
+
+local niches = { {03,01}, {03,09}, {07,01}, {07,09}, {11,01}, {11,09} };
+shuffle(niches);
+
+des.ladder("down", 11,05)
+-- The lord and his court
+des.monster("Vlad the Impaler", 06, 05)
+des.monster("V",niches[1])
+des.monster("V",niches[2])
+des.monster("V",niches[3])
+des.monster("V",niches[4])
+des.monster("V",niches[5])
+des.monster("V",niches[6])
+-- The doors
+des.door("closed",08,03)
+des.door("closed",10,03)
+des.door("closed",03,04)
+des.door("locked",10,05)
+des.door("locked",08,07)
+des.door("locked",10,07)
+des.door("closed",03,06)
+-- treasures
+des.object("chest", 07,05)
+
+des.object("chest",niches[6])
+des.object("chest",niches[1])
+des.object("chest",niches[2])
+des.object("chest",niches[3])
+des.object({ id = "chest", coord=niches[4],
+             contents = function()
+                des.object({ id = "wax candle", quantity=math.random(4,8) })
+             end
+});
+des.object({ id = "chest", coord=niches[5],
+             contents = function()
+                des.object({ id = "tallow candle", quantity=math.random(4,8) })
+             end
+});
+-- We have to protect the tower against outside attacks
+des.non_diggable(selection.area(00,00,14,10))