2019-08-19 PS
rwGRIB2.f90 subroutine readlatlon: check alloc status deallocate values
  - in case of empty input file 
  NOTE: check why we run into that at all!
  Improve by realloc only if dim has changed

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