Add Polar2Grid reader for CSPP VIIRS EDR Aerosol Optical Depth

[kathys]

Please create a new reader for the CSPP VIIRS EDR Aerosol Optical Depth product.

File name pattern: JRR-AOD*.nc

Array name: float AOD550

unitless

Valid range: -0.05 to 5.0 _FillValue: -999.999

This should be very similar to the Geo2Grid ABI product that is requested from the GEO side: https://github.com/ssec/polar2grid/issues/612

including the same color table used.

Test files:

bumi:/data/users/kathys/test_data/viirs_edr/npp/asci bumi:/data/users/kathys/test_data/viirs_edr/j01/asci