Move scriptapi to separate folder (by sapier)

On the lua side, notably minetest.env:<function>(<args>) should now
be replaced by minetest.<function>(<args>).
The old way is and will stay supported for a long time.

Also:
Update and clean up lua_api.txt (by celeron55)
Move EnvRef to lua and remove add_rat and add_firefly (by kahrl)
Add separate src/util/CMakeLists.txt, other minor fixes (by kahrl)

src/script/cpp_api/s_env.cpp

@@ -0,0 +1,132 @@
+/*
+Minetest
+Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "cpp_api/s_env.h"
+#include "common/c_converter.h"
+#include "log.h"
+#include "environment.h"
+#include "lua_api/l_env.h"
+
+extern "C" {
+#include "lauxlib.h"
+}
+
+void ScriptApiEnv::environment_OnGenerated(v3s16 minp, v3s16 maxp,
+		u32 blockseed)
+{
+	SCRIPTAPI_PRECHECKHEADER
+
+	// Get minetest.registered_on_generateds
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "registered_on_generateds");
+	// Call callbacks
+	push_v3s16(L, minp);
+	push_v3s16(L, maxp);
+	lua_pushnumber(L, blockseed);
+	runCallbacks(3, RUN_CALLBACKS_MODE_FIRST);
+}
+
+void ScriptApiEnv::environment_Step(float dtime)
+{
+	SCRIPTAPI_PRECHECKHEADER
+	//infostream<<"scriptapi_environment_step"<<std::endl;
+
+	// Get minetest.registered_globalsteps
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "registered_globalsteps");
+	// Call callbacks
+	lua_pushnumber(L, dtime);
+	runCallbacks(1, RUN_CALLBACKS_MODE_FIRST);
+}
+
+void ScriptApiEnv::initializeEnvironment(ServerEnvironment *env)
+{
+	SCRIPTAPI_PRECHECKHEADER
+	verbosestream<<"scriptapi_add_environment"<<std::endl;
+	setEnv(env);
+
+	/*
+		Add ActiveBlockModifiers to environment
+	*/
+
+	// Get minetest.registered_abms
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "registered_abms");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	int registered_abms = lua_gettop(L);
+
+	if(lua_istable(L, registered_abms)){
+		int table = lua_gettop(L);
+		lua_pushnil(L);
+		while(lua_next(L, table) != 0){
+			// key at index -2 and value at index -1
+			int id = lua_tonumber(L, -2);
+			int current_abm = lua_gettop(L);
+
+			std::set<std::string> trigger_contents;
+			lua_getfield(L, current_abm, "nodenames");
+			if(lua_istable(L, -1)){
+				int table = lua_gettop(L);
+				lua_pushnil(L);
+				while(lua_next(L, table) != 0){
+					// key at index -2 and value at index -1
+					luaL_checktype(L, -1, LUA_TSTRING);
+					trigger_contents.insert(lua_tostring(L, -1));
+					// removes value, keeps key for next iteration
+					lua_pop(L, 1);
+				}
+			} else if(lua_isstring(L, -1)){
+				trigger_contents.insert(lua_tostring(L, -1));
+			}
+			lua_pop(L, 1);
+
+			std::set<std::string> required_neighbors;
+			lua_getfield(L, current_abm, "neighbors");
+			if(lua_istable(L, -1)){
+				int table = lua_gettop(L);
+				lua_pushnil(L);
+				while(lua_next(L, table) != 0){
+					// key at index -2 and value at index -1
+					luaL_checktype(L, -1, LUA_TSTRING);
+					required_neighbors.insert(lua_tostring(L, -1));
+					// removes value, keeps key for next iteration
+					lua_pop(L, 1);
+				}
+			} else if(lua_isstring(L, -1)){
+				required_neighbors.insert(lua_tostring(L, -1));
+			}
+			lua_pop(L, 1);
+
+			float trigger_interval = 10.0;
+			getfloatfield(L, current_abm, "interval", trigger_interval);
+
+			int trigger_chance = 50;
+			getintfield(L, current_abm, "chance", trigger_chance);
+
+			LuaABM *abm = new LuaABM(L, id, trigger_contents,
+					required_neighbors, trigger_interval, trigger_chance);
+
+			env->addActiveBlockModifier(abm);
+
+			// removes value, keeps key for next iteration
+			lua_pop(L, 1);
+		}
+	}
+	lua_pop(L, 1);
+}