[phenixbb] cif_as_mtz : column labels

a .cif has a bunch of labels (see below). the output .mtz has three: FOBS, SIGFOBS, R-free-flags ... without getting anyones' hands dirty, are the F's merged from the four correct columns, viz. F_plus, F_minus, (and sigmas)? -bryan (for pdb code, pls. off-list) labels in .cif : _refln.F_meas_au _refln.F_meas_sigma_au _refln.F_calc _refln.phase_calc _refln.pdbx_F_plus _refln.pdbx_F_plus_sigma _refln.pdbx_F_minus _refln.pdbx_F_minus_sigma _refln.pdbx_HL_A_iso _refln.pdbx_HL_B_iso _refln.pdbx_HL_C_iso _refln.pdbx_HL_D_iso