On multiblock validation, if it finds an IO block, set boolean to indicate that it was found and its location in world. The IO block stores the BlockPos of the controller. On break method for the IO block inform the controller that it no longer has the IO block, set it to false and remove the BlockPos.

If a type of IO block is found, don't set a second one. So there can be only one. If an IO block has a controller, don't allow it to be set to a second controller. This might solve the issues with the reactors.

Fixed in 50ad043