JPSSnagg

Implemented -t multiple products in option parse, separated comma list into
list of products, with consistency check with -g <geoproduct>.

src/nagg_main.c
    debug statments to print the product list.
src/nagg.h
    Added GEOFILE_GEOPRODUCT enum value for geolocation_t for the case of
    -g <geoproduct>.
src/nagg_posix.h
    Added HDstrchr macro.
src/nagg_options.c
    Added code to parse -t multiple products option, automatically look up
    Geolocation product for products, verify they use the same geolocation
    product, support the -g <geoproduct> option.

Tested: Koala (parsing is correct but make check failed.)