hkl peak labels missing on sinograms.sinogram.GrainSinogram.build_sinogram

[jonwright]

Minimum is to add the h,k,l labels and add the option to make a sinogram of some other property (like eta or tth).

Code existing in hc5185:

    dh = g.hkl - hklmin[:,np.newaxis]
    de = (g.etasigns.astype(int) + 1)//2
    #   4D array of h,k,l,+/-
    pkmsk = np.zeros( list(dh.max(axis=1) + 1 )+[2,], int )
    pkmsk[ dh[0], dh[1], dh[2], de ] = 1
    #   sinogram row to hit
    pkrow = np.cumsum( pkmsk.ravel() ).reshape( pkmsk.shape ) - 1
    #### THIS LINE = indexes into the pkmsk array
    pkhkle = np.arange( np.prod( pkmsk.shape ), dtype=int )[ pkmsk.flat == 1 ]
    #### THIS LINE = hkl indices (transpose for N,3 versus 3,N)
    pkindices = np.transpose(np.unravel_index(pkhkle, pkmsk.shape))  + np.concatenate( (hklmin, [0]) )

Needs to be added to the code. Option for getting things like eta or tth or ds (etc) sinograms would need some refactoring. Requires that the colfile is not modified between setup and compute.