A proposal for observation of Executive

[rtrepos]

Executive has no default observation method.
Since vle-1.1 values can be defined as user values with id.
I suggest one could add a default behavior of observation in a new output plugin.
The Executive::observation method sends on port e.g. "Vpz" a new UserValue that contains a pointer to a Vpz. The observation then writes the vpz into a file that ideally could be simulated.

[rtrepos]

Some comments:

• This functionnality could replace the dump function.
• If the executive modifies the condition before calling createModelFromClass, the behavior of the simulation of the vp created could be different.

[quesnel]

Closing now. Feel free to submit a PR. Thanks.