Allow long lines for free format fortran code

[juhanikataja]

Problem is that in some places we preprocessor inserts paths in the fortran code (e.g. ModelDescription.F90:2619). It works fine on desktop but when the paths are long the line is truncated after preprocessing and weird error messages result.

Simple solution would be just to add fortran compilation flag that allows long lines. For gfortran it is -ffree-line-length-none.