add lua libs for lua map generator, also add bindings for mt rng

Tested to work with this test scenario, and the mainline defaults:

     [label]
         x = {X}
         y = {Y}
         text = {STRING}
     [/label]
[multiplayer]
    id=lua_map_gen
    name= _ "Lua Map Gen Test Scenario"
    description= _ "test test test of lua map gen"
    map_generation="lua"
    [generator]
        id="test"
	config_name="Test Lua Map Generator"
	create_map = << local rng = Rng:create()

			print(rng:draw())
			print(rng:draw())
			print(rng:draw())

			local w = 50
		        local h = 40

			map=""
			for y=1,h do
			  local r = rng:draw() % 2
			  for x=1,w do
                            if x == 10 and y == 10 then
                              map = map .. " 1 "
 			    end
                            if x == (w-10) and y == (h-10) then
                              map = map .. " 2 "
 			    end
			    if ((x + y) % 2) == r then
			      map = map .. "Gg"
			    else
			      map = map .. "Md"
			    end
                            if x ~= w then
                              map = map .. ","
                            end
                          end
                          map = map .. "\n"
                        end
                        return map
                     >>
    [/generator]

    id = foo
    random_start_time=yes

    {DEFAULT_SCHEDULE}
    [event]
        name=prestart
        {LABEL 25 20 ("Lua map generator")}
    [/event]

    [side]
         [ai]
             villages_per_scout=8
         [/ai]
         id=RBY_Side1
         side=1
         save_id=RBY_Side1
         persistent=yes
         color=red
         team_name=Red
         user_team_name= _ "teamname^Red"
         controller=human
         canrecruit=yes
         shroud=no
         fog=no
         gold=1000000
    [/side]
    [side]
         [ai]
             villages_per_scout=8
         [/ai]
         id=RBY_Side2
         side=2
         save_id=RBY_Side2
         persistent=yes
         color=blue
         team_name=Blue
         user_team_name= _ "teamname^Blue"
         controller=human
         canrecruit=yes
         shroud=no
         fog=no
         gold=1000000
    [/side]
[/multiplayer]

src/generators/lua_map_generator.cpp

@@ -20,6 +20,8 @@
 #include "lua/lua.h"
 #include "lua/lualib.h"
 
+#include "mt_rng.hpp"
+
 #ifdef DEBUG_LUA
 #include "scripting/debug_lua.hpp"
 #endif
@@ -30,6 +32,120 @@
 
 #include <boost/foreach.hpp>
 
+
+// Add compiler directive suppressing unused variable warning
+#if defined(__GNUC__) || defined(__clang__) || defined(__MINGW32__)
+#define ATTR_UNUSED( x ) __attribute__((unused)) x
+#else
+#define ATTR_UNUSED( x ) x
+#endif
+
+// Begin lua rng bindings
+
+using rand_rng::mt_rng;
+
+static const char * Rng = "Rng";
+
+static int impl_rng_create(lua_State* L);
+static int impl_rng_destroy(lua_State* L);
+static int impl_rng_seed(lua_State* L);
+static int impl_rng_draw(lua_State* L);
+
+static void initialize_lua_state(lua_State * L)
+{
+	// Open safe libraries.
+	// Debug and OS are not, but most of their functions will be disabled below.
+	static const luaL_Reg safe_libs[] = {
+		{ "",       luaopen_base   },
+		{ "table",  luaopen_table  },
+		{ "string", luaopen_string },
+		{ "math",   luaopen_math   },
+		{ "debug",  luaopen_debug  },
+		{ "os",     luaopen_os     },
+		{ NULL, NULL }
+	};
+	for (luaL_Reg const *lib = safe_libs; lib->func; ++lib)
+	{
+		luaL_requiref(L, lib->name, lib->func, 1);
+		lua_pop(L, 1);  /* remove lib */
+	}
+
+	// Disable functions from os which we don't want.
+	lua_getglobal(L, "os");
+	lua_pushnil(L);
+	while(lua_next(L, -2) != 0) {
+		lua_pop(L, 1);
+		char const* function = lua_tostring(L, -1);
+		if(strcmp(function, "clock") == 0 || strcmp(function, "date") == 0
+			|| strcmp(function, "time") == 0 || strcmp(function, "difftime") == 0) continue;
+		lua_pushnil(L);
+		lua_setfield(L, -3, function);
+	}
+	lua_pop(L, 1);
+
+	// Disable functions from debug which we don't want.
+	lua_getglobal(L, "debug");
+	lua_pushnil(L);
+	while(lua_next(L, -2) != 0) {
+		lua_pop(L, 1);
+		char const* function = lua_tostring(L, -1);
+		if(strcmp(function, "traceback") == 0) continue;
+		lua_pushnil(L);
+		lua_setfield(L, -3, function);
+	}
+	lua_pop(L, 1);
+
+	lua_settop(L, 0);
+
+	// Add mersenne twister rng wrapper
+
+	luaL_newmetatable(L, Rng);
+
+	static luaL_Reg const callbacks[] = {
+		{ "create",         &impl_rng_create},
+		{ "__gc",           &impl_rng_destroy},
+		{ "seed", 	    &impl_rng_seed},
+		{ "draw",	    &impl_rng_draw},
+		{ NULL, NULL }
+	};
+	luaL_setfuncs(L, callbacks, 0);
+
+	lua_pushvalue(L, -1); //make a copy of this table, set it to be its own __index table
+	lua_setfield(L, -2, "__index");
+
+	lua_setglobal(L, Rng);
+}
+
+int impl_rng_create(lua_State* L)
+{
+	mt_rng * ATTR_UNUSED(rng) = new ( lua_newuserdata(L, sizeof(mt_rng)) ) mt_rng();
+	luaL_setmetatable(L, Rng);
+
+	return 1;
+}
+int impl_rng_destroy(lua_State* L)
+{
+	static_cast< mt_rng * >( lua_touserdata( L , 1 ) )->~mt_rng();
+	return 0;
+}
+int impl_rng_seed(lua_State* L)
+{
+	mt_rng * rng = static_cast<mt_rng *>(luaL_checkudata(L, 1, Rng));
+	std::string seed = luaL_checkstring(L, 2);
+
+	rng->seed_random(seed);
+	return 0;
+}
+int impl_rng_draw(lua_State* L)
+{
+	mt_rng * rng = static_cast<mt_rng *>(luaL_checkudata(L, 1, Rng));
+
+	lua_pushnumber(L, rng->get_next_random());
+	return 1;
+}
+
+// End Lua Rng bindings
+
 lua_map_generator::lua_map_generator(const config & cfg)
 	: id_(cfg["id"])
 	, config_name_(cfg["config_name"])
@@ -45,6 +161,8 @@ lua_map_generator::lua_map_generator(const config & cfg)
 			throw mapgen_exception(msg);
 		}
 	}
+
+	initialize_lua_state(mState_);
 }
 
 lua_map_generator::~lua_map_generator()