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.

include/global.h

@@ -46,7 +46,7 @@
 #define ENGRAVEFILE "engrave"   /* random engravings on the floor */
 #define BOGUSMONFILE "bogusmon" /* hallucinatory monsters */
 #define TRIBUTEFILE "tribute"   /* 3.6 tribute to Terry Pratchett */
-#define LEV_EXT ".lev"          /* extension for special level files */
+#define LEV_EXT ".lua"          /* extension for special level files */
 
 /* Assorted definitions that may depend on selections in config.h. */