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_entity.h

@@ -0,0 +1,50 @@
+/*
+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.
+*/
+
+#ifndef S_ENTITY_H_
+#define S_ENTITY_H_
+
+#include "cpp_api/s_base.h"
+#include "irr_v3d.h"
+
+class ObjectProperties;
+class ToolCapabilities;
+
+class ScriptApiEntity
+		: virtual public ScriptApiBase
+{
+public:
+	bool luaentity_Add(u16 id, const char *name);
+	void luaentity_Activate(u16 id,
+			const std::string &staticdata, u32 dtime_s);
+	void luaentity_Remove(u16 id);
+	std::string luaentity_GetStaticdata(u16 id);
+	void luaentity_GetProperties(u16 id,
+			ObjectProperties *prop);
+	void luaentity_Step(u16 id, float dtime);
+	void luaentity_Punch(u16 id,
+			ServerActiveObject *puncher, float time_from_last_punch,
+			const ToolCapabilities *toolcap, v3f dir);
+	void luaentity_Rightclick(u16 id,
+			ServerActiveObject *clicker);
+};
+
+
+
+#endif /* S_ENTITY_H_ */