Items for mpgrafic development

* TODO (v0.4 or later)

- debianisation - debian directory for preparing debian packets

- update from fftw2 dependence to fftw3 dependence:
   - help: http://www.fftw.org/doc/Upgrading-from-FFTW-version-2.html
   - in principle straightforward, but the upgrade has to
      be done for the mpi, fortran90 version of fftw3

- replace declarations such as "real(kind=n)", where n is an integer,
   by more portable values;
   - https://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/Kind-Notation.html
   - https://gcc.gnu.org/onlinedocs/gfortran/KIND-Type-Parameters.html
   - one line in src/mpnorm.f90, many lines in random.f90

- debate/decide: retain random.f90 for users unable/unwilling to
   install GSL? or remove it?

- debate/decide: update from GPLv2+ to GPLv3+ ?
   Why: https://www.gnu.org/licenses/quick-guide-gplv3.html

- doxygen documentation extractable from source code

- test routines + frontends so that "make check" will test that a
   build of mpgrafic gives consistent results with builds on systems
   on which mpgrafic is judged to work correctly

- add yorick/ directory with yorick scripts

* DONE
