Finished the framework for all doubleCompare based classes. Still need
to be acutally implemented within factory
Added DoubleMathematical class for doing stuff with mathematical
operands on DoubleLiteralReturntype objects
Added DoubleAddition
Added DoubleSubtration
Added DoubleMultiplication
Added constructors for SubExpressions DoubleAddition, DoubleSubtraction,
DoubleMultiplication, DoubleDivision
Added DoubleSquareRoot
Added DoubleSine
added DoubleCosine
Added constructors for SubExpressions DoubleSquareRoot, DoubleSine,
DoubleCosine