3D data assembly .3da files

To assemble 2D "/adi" diffraction intensity files into a 3D "/adi" file, it may be useful to have a simple ASCII text file format called .3da which would have lines:

  filename,theta_x,theta_y,shift_x,shift_y,i_scaling
  filename,theta_x,theta_y,shift_x,shift_y,i_scaling
  ...

The parameters theta_x and theta_y give the present guess of the 2D diffraction pattern's orientation in degrees. The parameters shift_x and shift_y give the shift (in pixels) of the center of each 2D "/adi" file relative to the usual position as defined in Sec. 1.4.3. The parameter i_scaling gives a multiplying factor for each file to scale its intensities to the 3D set's average.

It could be worthwhile for Xewald (Sec. 3.4) to be able to write out .3da files, and for Cewald (Sec. 3.5.1) to be able to read and write these files.