=======
SAB 2000-01-17: Change copyright to FSF.
SAB 2000-01-30: Turn off all debugging options with ./configure flag.
                (Do not give the -g flag to the compiler, set NDEBUG.)
SAB 2000-03-27: Add an author field to MdRecord?
SAB 2000-06-15: Rename data to artsdata, so that paths in example
                control files work both in the source tree and in the
                installed version. 
SAB 2000-06-17: Change interpolation in absorption part to interpp.
SAB 2000-08-10: Change define_wsv_data, etc. to be default
                constructors. That way, we don't have to call them
                explicitly.   
SAB 2000-08-16: - Implement abs_tags and wf_tags, also
                  abs_tagsDefine and wf_tagsDefine.
                - Change absComp to return absorption matrices only for 
                  wf_tags
SAB 2000-08-21: Some ideas for absorption:
                - Method lines_per_tgAddMirrorLines
                  Adds mirror lines for those transitions for which
                  the calculation frequency would be inside the
                  cutoff. 
		  Requires the lineshapes and the frequency grid as
                  input. 
		  This would remove the need for a special
                  implementation of the VVW line shape, only
		  Lorentz-type lineshape would be needed.

                - Method lines_per_tgRemoveOutsideCutoff
		  Remove all lines which would not contribute anything
                  due to lineshape frequency cutoff. Saves unnecessary
                  calls to lineshape function, which would only return
                  0.
		  Needs lineshapes and frequency grid as input.

		- Should it be enforced that the frequency grid is
                  sorted? If not, this must be done by the above
                  methods. 

		- Make a method to set the lineshape functions. (All
                  the rest is already there!)

SAB 2000-08-21: Give a nice error message if control file does not
                exist! (At the moment it just says `abgebrochen')

AvE 22.08.2000: check that partition funciton coefficients are valid, 
                some species are not defined, nevertheless a dummy
                partition function coefficient is given. check that 
                the returned value of the partition function (NOT
                the ratio) is larger than zero after calling.