Sync w Upstream Magritte

[seandenigris]

The upstream repo merged an important fix RE mementos. In some cases forms were failing validation due to nonexistent conflicts. It’s also possible that copies of objects could be saved instead of the actual objects

[chisandrei]

Made feenkcom/magritte#3. I think first we'll sync the master branches and then merge the master branch into the feenk branch

[JurajKubelka]

I think the upstream changes have been merged to GToolkit.
I created a magritte-metamodel/magritte#348 to push GToolkit changes into the upstream.

[svenvc]

This could be closed then ?

[JurajKubelka]

It could. I am waiting for the magritte-metamodel/magritte#348