2019-08-21 PS
introduce the "new" versions of source files:
    all .f90 free format
    code beautification
    regression test is OK

   make new local gfortran makefiles, remove parameters not needed
   anymore

   change filenames rwgrib.f90 (all lower), preconvert to calc_etadot,
   adapt messages and comments in calc_etadot.f90
   adapt all makefiles to new filenames
   adapt success message of logfiles in regression test references
   redo regression test OK

   provide softlinks for standards:
     calc_etadot.out -> calc_etadot_fast.out
     makefile_local_gfortran -> makefile_fast

provide changelog.txt in Fortran
provide readme.txt in Regression/FortranEtadot