Autolathe and material rewrite.

http://i.imgur.com/AJ9PvBj.png

First pass on making our material system more robust and useful.
- Removed m_amt, g_amt and w_amt.
- Added matter list for objects.
- Rewrote autolathe to use matter list and be less awful and more modular.

TODO: Add plastic to lathe, redo actual material values for items.