GH221 - Update tree when running sync actions
Merge remote-tracking branch 'origin/master' into GH221-codesync-descriptors-operations3
Merge pull request #297 from flower-platform/GH221-codesync-descriptors-operations3

Gh221 codesync descriptors operations3
Fail safe: edge with no models: diagram doesn't throw error any more
GH215 - issue solved: when collapse/expand compartment children are
reversed + models remain without renderers
Merge remote-tracking branch 'origin/master' into GH215-class-appearance-smaller
GH215 - issue solved: relations ends aren't calculated correctly at
initialization and when the source/target changes its width/height