This class facilitates building frameworks of several classes that
inter-operate.  It was first designed and built for "HTML::Mason", in which
the Compiler, Lexer, Interpreter, Resolver, Component, Buffer, and several
other objects must create each other transparently, passing the appropriate
parameters to the right class, possibly substituting other subclasses for
any of these objects. 

The main features of "Class::Container" are:

 *   Explicit declaration of containment relationships (aggregation, factory
     creation, etc.) 

 *   Declaration of constructor parameters accepted by each member in a class
     framework

 *   Transparent passing of constructor parameters to the class that needs
     them

 *   Ability to create one (automatic) or many (manual) contained objects
     automatically and transparently
