System of calling functions with side effects when an object goes out of scope.  Scoping
can be defined as gc-based scoping or stack-based scoping or a combination of the two of them
in which case the behavior becomes 'release-no-later-than'.

For GC resources, users must not reference the tracked object in the dispose function
else the circular dependency will keep the object in the gc's live set

System for using both weak and soft references generically.  Weak references don't
count for anything in the gc while soft references will keep their object alive as
long as there is no gc pressure.

Implementation of stack based resource system.  Simple, predictable, deterministic,
and applicable to most problems.  Resource contexts are sequences of resources that
need to be, at some point, released.