Minor changes for Python 3.x

Oops fixed

Adding in WolfSheepPredation

Adding parameters and fixing style issues
Merge pull request #27 from projectmesa/python3_compatibility

Python3 compatibility
Fixing readme for Python 3
Changing tabs to spaces

Well this is embarrassing...
Merge branch 'master' of github.com:projectmesa/mesa into Ascii_Server

Conflicts:
	mesa/space.py
	mesa/time.py