Minecraft: Spawn suppression on minecart tracks in the nether.

The next step in the development of the ghast farm is to suppress spawning on the minecarts tracks. Solution found, on to implementation.

Special thanks to endsgamer : http://www.youtube.com/user/endsgamer for helping me think this through to a working solution. Also many thanks to everyone's suggestions and feedback! ... https://www.youtube.com/watch?v=luVw0HMpE6o