ADDREG, COPYREG, etc. and MULTREGP, MULTREGT, etc. Add Note on Default Region

[gdfldm]

• If the REGION array is not indicated, the
• default region to use in the xxxREG keywords depends on the GRIDOPTS
• keyword:
• 1. If GRIDOPTS is present, and the NRMULT item is greater than zero,
• the xxxREG keywords will default to use the MULTNUM region.
• 2. If the GRIDOPTS keyword is not present - or the NRMULT item equals
• zero, the xxxREG keywords will default to use the FLUXNUM keyword.