added .gitignore file

See merge request mhm/mhm!1

  IDEs/editors and programming languages:
  - macOS
  - Windows
  - XCode
  - Vim
  - SublimeText
  - Emacs
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  - Python
  - Tex
  - Fortran

- fixed some bugs in formatting of files

- finalized beta version of format_doxygen_docs_in_f90.py
- fixed remaining update in documentations

         -reformatted many lines

- finalized script and rewrote doxygen strings for all routines except
  in lib (pre-interface strings not yet supported) 
- remaining failing test_cases (NAG will provide patch):
  - NAG fails with open-mp false during read-in of namelist
- still TODO: check write optimization restart file

- finalized beta version of format_doxygen_docs_in_f90.py
- fixed some typos in documentations

- merged branch mpr_extract
- remaining failing test_cases (NAG will provide patch):
  - NAG fails with open-mp false during read-in of namelist
- still TODO: check write optimization restart file
- still TODO: add documentation
  (will be done with pre-proc script format_doxygen_docs_in_f90.py)