Add textures for active mode of CNC.
Correct two typing bug in battery_box.lua
CNC can now change programs while it is working.
Slope box fixes. From Bas080.
Massive change to the way CNC programs are registered.
Now the API is open for adding new nodes and inhibiting some nodes for some materials.
No more recipes outside of the CNC machine.

Code length also greatly reduced.
Merge pull request #17 from kpoppel/master

Add more CNC stuff