gen5 - Fourier synthesis generator

	gen T gen5 F   h1,a1,p1  h2,a2,p2  . . .  hN,aN,pN;

Each Fourier component of the (open) function is described by a triplet
specifying a harmonic number, an amplitude, and a phase offset relative
to sine phase.  As many components may be supplied as desired, but all
three values must be supplied for each component. Phase angles are in
radians (cf. "Deg" post operator in expressions); harmonic numbers need 
not be integers.  Examples:

    gen 0 gen5 f1 1,1,0;		(f1 is a sine wave)
    gen 0 gen5 f2 1,1,0 3,1/3,0 5,1/5,0; (f2 is first 3 components square wave)
    gen 0 gen5 f3 1,-.5,90Deg 0,.5,90Deg; (f3 is a raised cosine wave)
