Four new classes:
- MoMLImporter: import a moml into a jiip internal model
- FSM, FSMState, FSM Transition: inherited classes from CompositeActor,
CompositeActor and Relation. For state machines handling.
Improvements needed.

Minor changes in the previous classes, added a "contains" method to
check if a NamedObj is contained or not, useful to avoid annoying
NullPointerExceptions.
Port link() method changed a little, now we use "addPort"; minor changes
in Relation too.

Test2.java : simple case study, read a model and print state machine.
Can also visit all the model.