Merge pull request #1 from jojuett/master

AI Stuff
mutated tractor object to custom Tractor game object subclass
manually added paintings until Blender texture replacement bug is fixed
fixed portal world loading bug
fixes bug #7
added sheep and ram models from yofrankie
first try at making sheep python interface
Merge remote-tracking branch 'upstream/master'

Conflicts:
	chars/tractor_scripts/ai_actions.py