Transmitter rendering improvements

Well that was easier than I thought it would be. Replaced the central box of the transmitter with 6 individual faces that render instead of the connected part of the transmitter, only when that face isn't connected.
![2013-07-08_01 31 35](https://f.cloud.github.com/assets/543022/758917/cbf2c7de-e765-11e2-8703-333a42e01cb2.png)
The insides of the centre faces render but the insides faces of the connected sides don't. I'm not sure if it's possible to stop it from back-face culling but that would fix that.