Update: Making Pool.Free capable of "deep freeing" Motivation: Since we're getting rid of custom "FreeList" calls, then we should also remove FreeListAndItems, the last custom func in the "Free" set. - Collections-related Free overload now can deep-free - calling Free on all elements of a collection. - Marked FreeListAndItems as obsolete (with error) and piped it over to Free overload - Updated 4 callsites of FreeListAndItems to use Free(T, true) instead Tests: built all targets.