This sample script shows the use of weak references in ROT.
Roles get as long maintained as they are needed. If the base object
gets finalized, the role is deleted too, automatically.

Please note: The garbage collector need two cycles to sweep all roleobjects:
 -the first cycle: the base objects get finalized and all relations to its roles
 -the second cycle: all role objects get finalized

There is a time gap between both cycles, where roles can exist without a valid base.
This can lead to problems only, by use of externalized roles. 
