Redstone stuff

Hi, 

Here's some redstone wire related stuff I've been playing with. 

I added some drone functions for laying down redstone wire with supporting blocks, with repeaters (in a straight line), and a redstone-lined road example.

Hope I have not overlooked some easier way to do this :)  (took a bit of trial and error)
![2013-03-16_03 50 59](https://f.cloud.github.com/assets/61715/266605/a6c6d476-8e16-11e2-959b-913353b9b8f0.png)

- Matt