feat: Multi-polarization anisotropy in RSoXS module

[pbeaucage]

Implement handling of multiple polarizations... template following this code from Eliot, but is this the best way to do this? something something spherical harmonics?

// use the parallel and perpindicular waves to calculate A (anisotropy) for each polarization, then average as possible to create a single A

	if(waveexists(parah) &&waveexists(perph))
		make /o/n=1000 $cleanupname(basename+"_Ah",1), $cleanupname(basename+"_Ahx",1)
		wave Ah = $cleanupname(basename+"_Ah",1)
		wave Ahx = $cleanupname(basename+"_Ahx",1)
		minq=max(wavemin(parahx),wavemin(perphx))
		maxq = min(wavemax(parahx),wavemax(perphx))
		setscale /i x,minq,maxq, Ah, Ahx
		Ahx = x
		Ah = (interp(Ahx,parahx,parah) - interp(Ahx,perphx,perph))/(interp(Ahx,parahx,parah) + interp(Ahx,perphx,perph))
		duplicate /o Ah,  $cleanupname(basename+"_A",1)
		duplicate /o Ahx, $cleanupname(basename+"_Ax",1)
		wave A = $cleanupname(basename+"_A",1)
		wave Ax = $cleanupname(basename+"_Ax",1)
	endif
	if(waveexists(parav) && waveexists(perpv))
		make /o/n=1000 $cleanupname(basename+"_Av",1), $cleanupname(basename+"_Avx",1)
		wave Av = $cleanupname(basename+"_Av",1)
		wave Avx = $cleanupname(basename+"_Avx",1)
		minq=max(wavemin(paravx),wavemin(perpvx))
		maxq = min(wavemax(paravx),wavemax(perpvx))
		setscale /i x,minq,maxq, Av, Avx
		Avx = x
		Av = (interp(Avx,paravx,parav) - interp(Avx,perpvx,perpv))/(interp(Avx,paravx,parav) + interp(Avx,perpvx,perpv))
		if(waveexists(A))
			minq=min(wavemin(Avx),wavemin(Ahx))
			maxq=max(wavemax(Avx),wavemax(Ahx))
			setscale /i x,minq,maxq, A,Ax
			Ax=x
			A = x>=wavemin(Avx) && x<=wavemax(Avx) ? interp(x,Avx,Av) : 0
			A+=x>=wavemin(Ahx) && x<=wavemax(Ahx) ? interp(x,Ahx,Ah) : 0
			A /= x>=wavemin(Ahx) && x<=wavemax(Ahx) && x>=wavemin(Avx) && x<=wavemax(Avx) ? 2 : 1
		else
			duplicate /o Av,$cleanupname(basename+"_A",1)
			duplicate /o Avx,$cleanupname(basename+"_Ax",1)
			wave A = $cleanupname(basename+"_A",1)
			wave Ax = $cleanupname(basename+"_Ax",1)
		endif
	endif

[pbeaucage]

This was partially addressed in 545558f

Needs that remain:

• offer a canned option to normalize by the intensity at some known, non-resonant energy (for density scatter)
• warn if one polarization is systematically lower/higher than the other
• eventually, a spherical harmonics based approach would be really cool. (this is non-blocking).