Handle polygon based dimension information
- parser for shapefile format
- do research on storage format for icosahedrial grids (How are abbreviations like T32 translated internally - (reference cdo manual or standard work on atmospheric modelling))
- namelist section Dimension must support additional fields for polygon-based input (e.g. dim_files shall support path to shapefile and area_dims accepting a tuple of dimensions)
- use our Fortran library routine polytest to create weights
- implement issue #33 first which supports multi-dimensional weight creation