#27 else-ref history

[AB]

In the case you have a <participant ref="principal"
else-ref="alternative"/> to handle failures on
the "principal" one:
the wflow history does not keep track of the failure
on the "principal" participant nor the success on
the "alternative" participant.
In fact, at the end of the "alternative" participant
action (succesfully ended) the history
states "principal" participant "ok", as
the "principal" had performed successfully.

The history could instead highlight this particular
situation as:
participant: principal
text: failure
pariticpant: alternative
text: ok

This could be useful to understand the actual
workflow. Today is not in fact possible
distinguishing the case of success or failure of the
principal.