update CLUBB externals to use CAM vertical indexing

[adamrher]

What is the feature/what would you like to discuss?

Update CLUBB externals to use CAM vertical indexing convention (top-down). CLUBB currently uses bottom-up indexing, requiring duplicate arrays for holding the flipped variables, which are fed into the main CLUBB call. Removing the need to flip arrays should improve performance.

Is there anyone in particular you want to be part of this conversation?

@Katetc @vlarson @huebleruwm

Will this change (regression test) answers?

I Don't Know

Will you be implementing this enhancement yourself?

Yes

[vlarson]

@adamrher:

 @huebleruwm is ready and willing to help with this ticket.  How should he begin?  When will CAM7 be frozen?

[adamrher]

I've been bogged down with other stuff, but Gunther is free to start working on implementing this into the head of cam_development now. I should be able to be more engaged in a week or two, and can field any questions in the meantime.

As long as we can maintain backwards compatibility with the settings / parameter values in the current version on cam_development, answer changes due to this more efficient infrastructure (not flipping arrays) should be fine until at least the end of the calendar year.