Add fmod function to TMath

I propose to add fmod function to TMath.
It is the following:

Compute remainder of division

Returns the floating-point remainder of numerator/denominator.

The remainder of a division operation is the result of subtracting the integral quotient multiplied per the denominator from the numerator:
remainder = numerator - quotient * denominator


and use


I guess it’s better, than #include <TMath.h> and call TMath::Fmod which in turn will call std::fmod.