Refactor and document API of the semantic layout
Use new semantic layout API in the interactive controller

+ other improvements. E.g. layout algorithm now isn't triggered during
model reset, what is unnecessary.
Repaint view when Model View is reset

Previously this bug was hidden, as repaint was triggered using some
accidental, weird logic (due to resize() callback, which was
unnecessary during reset).
Ensure that layout alg. is be triggered only once in non-iframe mode