Mutable modules

[David M. Lloyd]

Related to #MutableConfigurations, in order to support dynamically 
changing deployments for containers (including, I believe, 
OSGi-compliant containers) where deployments are modules, it is 
necessary to allow a module's dependency graph to be mutated at run 
time.  The behavior of such things in existing systems is such that any 
already-loaded/linked dependency classes remain, thus such action is 
usually only guaranteed to be "safe" when adding dependencies, or when 
it can be somehow guaranteed that no lingering dependency classes exist, 
or that such lingering classes can safely be ignored.

While this operation isn't 100% safe, it is supported by containers in 
existence today, so should at least be considered.
-- 
- DML