Actually fix weather

The real problem was that MapBlocks were not activated before getting sent to the client

src/map.h

@@ -403,6 +403,9 @@ public:
 
 	*/
 	MapBlock * emergeBlock(v3s16 p, bool create_blank=true);
+	
+	// Carries out any initialization necessary before block is sent
+	void prepareBlock(MapBlock *block);
 
 	// Helper for placing objects on ground level
 	s16 findGroundLevel(v2s16 p2d);