JPSSnagg

Revised the  patch to support multiple platforms because unlike the
N_GEO_Ref attribute, which according to the JPSS Common Data Format
Control Book Volume V is used only where the geolocation information for
a particular data product is packaged separately, all data products
including GEO products should have a Platform_Short_Name attribute:
1.      Removed get_platform_short_name(), which I believe was a clone
of get_geofile_refs(), and instead called get_platform_value() directly.
2.      Added the 4 character buffer to the granule_t structure that is
created for each granule and allocated the memory to store the
spacecraft code as part of that structure.
3.      Removed unused variables I, j, pos and duplicate_geo_file from
get_platform_value() and renamed the function’s 2nd parameter.
4.      Moved #define PLATFORM_NAME_SIZE 4 from nagg_get_granules.c to
nagg.h as NAGG_PSN_size for use also in
nagg_select_granules.c/compose_output_fname().
5.      Added a call to get_platform_value() to get_geo_granules() to
get the platform name for GEO granules as well as data product granules.
It’s simplest to put the value from the attribute into the granule_t
structure for every granule.  One test failed to add the platform name
to the output file name because compose_output_fname() pulled the
platform name from a GEO granule.
6.      Removed the char *spcrft parameter added to
compose_output_fname(). The function now gets the platform name from the
structure for the first selected granule passed to it.
7.      Made the Spacecraft ID in the output filename lower case.  The
listed Identifiers under Applicable Values in the Control Book Volume I
are lower case, and they have been lower case in all of the files I have
seen.

I've also added a few minor changes otherwise to correct an issue we
were seeing on a ppc64 system, to eliminate some compiler warnings, and
changes to expected output files to reflect the addition of the platform
short name to the nagg granule structures.

Added the ACKNOWLEDGEMENTS file.