converted some index values to 8-byte

[edwardhartnett]

Part of #653

Converting some 4-byte values in the index to 8-byte values in the index.

[AlexanderRichert-NOAA]

Testing this with tocgrib2 and the test file from the RRFS devs, if I use getgb2p, it segfaults (on the line where it sets the first of the four 7's), and if I use getgb2p2, it doesn't seem to resolve the missing 7777 problem.

[edwardhartnett]

It would be helpful if you could approve this and I can merge it, as I continue to solve the problems with > 2GB that I recently learned of from Wesley.

I'm not working on the 7777 problem yet, but the first step will be an automated test that demonstrates the problem. Do we have that yet?

Is the 7777 problem in tocgrib2 or g2? Do we know? If it is in g2, we should have a g2 test that demonstrates it without involving tocgrib2.

Is there an issue for the 7777 problem? If not, can you create one?

[AlexanderRichert-NOAA]

Yes the issue is in g2, I just created an issue for it: #666
@edwardhartnett if you're able to keep on with the coding side I can work on setting up a CTest test using the RRFS file.