Associating feature with existing aspect does not update feature visually

[Matthias Schoettle]

When I associate a feature with an existing aspect, it is correctly added to the list of models, however, the feature is not visually updated to indicate that is is realized by a model.

Steps to reproduce:

1. Create aspect without realizing a feature
2. Create a feature
3. Tap-and-hold on feature and select "Associate Aspect*
4. Select the aspect

If I save and reopen the concern, it is visualized correctly (indicating that the model was changed before).

[Cécile Camillieri]

Merge branch Feature-Model-Improvements: several feature model fixes and improvements (see pull request 43 for details) (resolves #323).

→ <<cset 13b05550f78f>>