#186 Display/store Information Type

A Message Link in the scenario editor has a property named "Message Type". This is currently displaying either the Element or Type properties of an Information Type from a choreography.

1. The Message Link property of Message Type must display the name of the Information Type, not the element or type property of the Information Type. The .scn file should also contain the Information Type and not the element or type values.
2. The Information Type must be able to be added to the Scenario even though it is not yet part of the Choreography. This is part of the SRT incremental method where the expected order is:
a - Capture the scenario
b - Add the information types to the message type in the scenarios
c - Add the information types to the choreography to support the scenario

# This solves the problem where different Information Type element or property have the same name and are otherwise indistinguishable.
# The annotation by Information Type might be possible even though the element or type properties of the Information Type are not known. It is the Information Type that is the semantics of the choreography, not its concrete expression in XML. For example, think of non-XML Information Types.