Made Gates and wires glow in the dark when active

As requested at #2323
 
Note: Some texture re-work might be necessary... I think the current
lit texture are far too bright.

Found a bug: popping a gate out of the pipe doesn't update it on the
client side (a.k.a. the gate pops out but is still rendered on the pipe)

Day (as you can see everything looks far too bright when active):
![screen shot 2014-12-19 at 16 17 47](https://cloud.githubusercontent.com/assets/5294529/5509054/e32c0934-879a-11e4-8c49-dc9e007d2bdd.png)

Night (looks gorgeous ;D):
![screen shot 2014-12-19 at 16 17 41](https://cloud.githubusercontent.com/assets/5294529/5509058/f0d5cad4-879a-11e4-842e-7d670fedddaf.png)