Addition and multiplication methods and Improvement to other simplification methods

Removed groupMultiple, expandUnaryNeg,  all recur_ methods, reducePartial, 

Rewrote equal, reduce, flatten, simplifyTerm, delIdentity, groupNegative, mulZero, reduceNumber, 

Added groupDivide, expand, opSimp,

Added Function subtrait to Term, and  Basic Exponential and logarithm functions.