Drydep coupling for CAM

[marysa]

We currently pass dust fluxes up to the atmosphere, which SLIM gets from the SLIM input file. But for dry deposition, it doesn't look like the land model directly hands the atmospheric model a flux; rather, it looks like CAM is trying to figure out what the dry deposition should be, and from discussion with the CAM folks, it does this based on properties of the land surface. This isn't happening when coupled to SLIM. I haven't yet figured out exactly how CAM is doing this thus am not yet sure how to get it to work with SLIM.

[marysa]

Calling this both a bug an and enhancement because it runs without the drydep coupled, but it is probably leading to drift in the chemistry fields of the atmospheric model.