[phenixbb] auto-open MTZ scheme

[Ralf W. Grosse-Kunstleve]

Another idea: we could use the history lines to communicate in a flexible
way what we want the browser to auto-open. E.g.

  auto_open = 2FOFCWT PH2FOFCWT
  auto_open = 2FOFCWT_fill PH2FOFCWT_fill

would ask the viewer to open these two maps when the mtz file is read.

Then we could even provide a mechanism for users to select themselves
what maps are automatically opened, e.g.:

  phenix.refine.electron_density_maps {
    map {
      mtz_label_amplitudes = my_map.f
      mtz_label_phases = my_map.phi
      likelihood_weighted = True
      obs_factor = 3
      calc_factor = 2
      kicked = True
      fill_missing_f_obs_with_weighted_f_model = True
      viewer_auto_open = True
    }
  }

This could be taken further:

  auto_open = important_refine_003.pdb
  auto_open = 2FOFCWT PH2FOFCWT
  auto_open = 2FOFCWT_fill PH2FOFCWT_fill

Maybe with extra settings:

  auto_open = 2FOFCWT PH2FOFCWT contour_level=3 rgb=0,0,1
  auto_open = 2FOFCWT_fill PH2FOFCWT_fill contour_level=3 rgb=0,1,0

Ralf