Generate GeoTIFFs with compressed 1-bit channel
Use simple packing for GRIB2

Complex packing with spatial differencing resulted in invalid GRIB files
Add result files in GeoTIFF and GRIB2 format
Add README
Use positive value for j-direction increment

The sign will be already flipped for north-to-south direction by flags.
This should be the absolute step size.
Longitude [0°, 360°] instead of [-180°, 180°]

GRIB2 uses [0, 360] exclusively to avoid the ambiguitites in the
longitude values that GRIB1 had