Number constant ops

[rnett]

Adds a constant ops that takes Number and a TNumber class, and one that does the same based off of an Operand's runtime type. The conversion is done using Number.doubleValue() etc rather than cast, since it avoids adding an op, and is necessary to call the other constant ops. It's useful when you want to create a composite op that works with any numeric types, but need to add a constant, or for enabling things like the + operator in Kotlin to not need a new overload for each scalar type.

[karllessard]

Thanks @rnett !