InheritanceToMemberRule was disabled in the default InferenceAgent. Re-enable it.
Inference history was disabled. Re-enable it, using the main atomspace, and don't 'copy' atoms.
formulas.py contains duplicate definitions of 'inheritanceFormula'. Disable one.
Update docstring formatting for GeneralEvaluationToMemberRule
Add inference agent for Tuffy 'smokes' example
Add inference agent for Tuffy 'smokes' example
Update __init__.py for module
Merge pull request #573 from cosmoharrigan/pln-updates

PLN: example agent for Tuffy 'smokes' problem, plus some small updates