New header parameters or facilities

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New header parameters or facilities

A number of new objects have been added to the header in addition to all the previous ones.

- For the programmer convenience, 3 pointers to the ref(:), val(:) and inc(:) values are now available, allowing easy writing of loops on the dimensions. They are real Fortran pointers to (and not duplicate of) the convert array from the coordinate section2.
- In the extrema section, the min and max value coordinates in the cube are coded in memory as a MINLOC and MAXLOC arrays with 7 elements. In the disk file, they are coded as 2 flat (scalar) address in the data.
- The Doppler factor (dopp) and the velocity type (vtyp) have been added to the spectroscopy section.