Update models only once on init

[SuslikV]

Because view models has same origin, there is no sense to update models from the each view during initialization.

Now log-file shows that same models are updated twice on init (one for each View). This PR removes this excessive update on View init.

[ferdnyc]

I'm on my phone right now and can't get a REALLY good look at it, but makes total sense to me. 👍

We probably don't even need the call to self.refresh_columns() in the view __init__()s, since by then it'll be connected to the signal that the model will emit after refresh.

[ferdnyc]

In fact, now I'm wondering if the model refresh shouldn't be delayed until after the project file is loaded (when one is being loaded) -- if it isn't already. (Again, phone. Can't remember.) Before then, there's nothing to refresh.

[ferdnyc]

Hrm. So, I was going to merge this (sorry for the delay, lost track of it), and then during a final quick test I actually spotted a difference from the current develop code.

In develop, if I have the Emojis filter selector set on one of the groups (e.g. 'Smileys'), then when I bring up OpenShot that group will be selected, since it's stored in my user settings.

But with this branch, the Emojis list always comes up showing all items — it doesn't respect the saved filter settings. Not sure why.

It might be because the refresh is being done before the dock is visible. If it's done after that point, the view refresh should happen automatically, because the signal's been connected. Might work to just move the update_model() calls down a few lines each, to after the `show() calls for the enabled View. (Or, alternately, that may be backwards. It may have to happen before the view objects are created.)

[ferdnyc]

Oh, yeah, moving the update_model() to before EmojisListView() is created fixes it, for that one. Which makes total sense come to think of it, because the View code makes use of the model data, when it's creating that dropdown list.

[jonoomph]

LGTM, seems to work in my testing