Corrected evaluateExprBound in two ways: added appropriate behavior when isit = 'n' and fixed the logic tree so that when the op is empty, the method searches for the variable values to return.
Corrected evaluateExprBound in two ways: added appropriate behavior when isit = 'n' and fixed the logic tree so that when the op is empty, the method searches for the variable values to return.

MyersResearchGroup/iBioSim,MyersResearchGroup/iBioSim,MyersResearchGroup/iBioSim