Retain data loaded from disk for multiple Calcs in a CalcSuite, rather than reloading each time about aospy HOT 2 OPEN

A nascent form of this functionality has been implemented in the aospy-obj-lib repo, but it is buggy and messy.

Also, important that the location-specific file access methods (e.g. the dmget or hsmget calls required to free files saved on the /archive of NOAA GFDL) be factored out of the other code to the fullest extent possible. Eventually want to support users at other institutions, and enable them to make their necessary system calls as they deem necessary.

from aospy.

This is partially being implemented in #155.

However, the aspect of holding onto data across calculations, which would definitely be useful, is not addressed there. So leaving this open.

from aospy.