Create combine factors method to combine the subfactors of a chain to
reduce loopiness
Make numVars and size available to other methods.
Define hasStar to detect whether any contained variable has star
Make valueSet available outside class
For chain using a regular discretization scheme adjust result to look
for 1 factor
Adjust test for model using chain and a condition on one output to
return correct value

Note this model is no longer "loopy"
Chain tests result in fewer factors.
Chain tests with temporary variables will have fewer result variables
Added single input CPD test.