refacto: rendering engine singleton removal step 1 (filesystem)

Make the RenderingEngine filesystem member non accessible from everywhere

This permits also to determine that some lua code has directly a logic to extract zip file. Move this logic inside client, it's not the lua stack role to perform a such complex operation

Found also another irrlicht <1.8 compat code to remove

src/client/client.h

@@ -45,6 +45,7 @@ struct ClientEvent;
 struct MeshMakeData;
 struct ChatMessage;
 class MapBlockMesh;
+class RenderingEngine;
 class IWritableTextureSource;
 class IWritableShaderSource;
 class IWritableItemDefManager;
@@ -123,6 +124,7 @@ public:
 			NodeDefManager *nodedef,
 			ISoundManager *sound,
 			MtEventManager *event,
+			RenderingEngine *rendering_engine,
 			bool ipv6,
 			GameUI *game_ui
 	);
@@ -379,6 +381,9 @@ public:
 	// Insert a media file appropriately into the appropriate manager
 	bool loadMedia(const std::string &data, const std::string &filename,
 		bool from_media_push = false);
+
+	bool extractZipFile(const char *filename, const std::string &destination);
+
 	// Send a request for conventional media transfer
 	void request_media(const std::vector<std::string> &file_requests);
 
@@ -469,6 +474,7 @@ private:
 	NodeDefManager *m_nodedef;
 	ISoundManager *m_sound;
 	MtEventManager *m_event;
+	RenderingEngine *m_rendering_engine;
 
 
 	MeshUpdateThread m_mesh_update_thread;