Write tests for model mem management code. about cyclus HOT 2 CLOSED

I just marked this as critical because it seems like related issues might have arisen during preliminary vision benchmarking exercises. If that's not correct, feel free to undo this and mark this issue subcritical.

from cyclus.

The issues that cropped up were related to memory management, but they were not necessarily related to the memory management code working improperly. The problems arose due to InstModel (and RegionModel) not being designed to handle the case where their children were being decommissioned/deallocated. In short, the problems were not deficiencies in the memory management code, but in incorrect assumptions models made about memory management. I still think this is very important, however, and I will keep it critical

from cyclus.