ADD: ability to adjust graph model, not only reset it.

[xulman]

The standard way to pause model listeners and "lock" the model for changes is via

new AbstractModelImporter< Model >(pluginAppModel.getAppModel().getModel()) {{ startImport(); }};
//my code here
new AbstractModelImporter< Model >(pluginAppModel.getAppModel().getModel()) {{ finishImport(); }};

But startImport involves cleaning of the model... since I was blind to find how to only update the model without cleaning it first, I propose this PR.

[xulman]

hmm, I haven't actually checked for something like AbstractModelUpdater.... (first ask before shoot, I know... sorry)

[xulman]

Hi, I've revamped this piece. It's been rebased to the latest master.

I could use such "official" way to pause listeners when updating graph, the original code was always clearing the graph. V.

[tinevez]

As suggested by Tobias elsewhere, another option would be to allow for controlling the listeners. Like have something like:

model.listeners().pause(); // pseudo code hein
try
{
    // Add, remove, do plenty of things in bulk
}
finally
{
    model.listeners().resume(); // fire listeners if a change happen.
}

What would you favor?

[tinevez]

@xulman do you still need this?