write a reader for meteo data in grib file format

[lars2015]

• enable direct use of meteo data in grib file format for MPTRAC (i.e., avoid having to convert grib to netCDF)

• ECMWF's eccodes library for handling grib data: https://confluence.ecmwf.int/display/ECC

• Tasks:

  • get started with MPTRAC model (follow instructions in README.md, look at projects/example)
  • get familiar with eccodes library for reading grib data: https://confluence.ecmwf.int/display/ECC
  • look at simple test cases/tutorial for reading data/messages from grib files
  • look at compilation/installation of eccodes and integrate it in the library build process of MPTRAC
  • write a new reader (read_met_grib()) for reading meteo data from grib files in MPTRAC
  • set up test case, integrate it in make check
  • write documentation (doxygen comments)