Log pile update

Updated log piles, the changes are:
* Updated the rendering to show the number of logs and what they are:
![2014-11-29_01 24 32](https://cloud.githubusercontent.com/assets/5393249/5235249/3f9edcd6-77ed-11e4-955d-5ca4a97b472d.png)
![2014-11-29_01 24 45](https://cloud.githubusercontent.com/assets/5393249/5235251/45053120-77ed-11e4-89af-ad0f4662d273.png)
![2014-11-29_01 25 56](https://cloud.githubusercontent.com/assets/5393249/5235253/6191243e-77ed-11e4-8b2d-10233fb25600.png)

* Log piles require a solid surface or they will eject. This prevents floating log piles when the one below has less than 16 logs.
* If a log pile has logs removed it will grab matching logs (or the first stack if you remove the entire stack) from the pile above so you can still access log piles at the bottom of stacked piles without it all falling down. If there aren't enough matching logs the piles above will collapse.

* Torches won't light a stack of log piles with less than 16 logs (if you have two stacks on top of another, the top one having less than 16, they will still light). This was done to prevent  torches, dropped from above, giving off sparks as it goes past where the top of the log pile would be if it was fully rendered. This could probably have been done better and I can change it if you would prefer.

I was going to also update pit kiln logs with a similar thing but I think that requires a separate pull request as it is technically a different update.

I have tested this in single player and SMP but, as I was testing by myself, there were certain things I was not able to test, such as two players doing stimulations actions.

If there is anything I have missed, overlooked or anything you think I may have broken let me know and I will fix it.