some internal changes to messaging related classes
beginning work on better policy expression
making Graph implement Closeable
typo
some updates to use of iterators in messaging-related classes
ongoing work on declarative link contract policies
more work on declarative policies
webtools update
some more work on iterators
bugfix in multiplicity
more unit tests and examples for policies
example fix
small updates to returning operation XRI and policy XRI
adding support for graph visualization