Minor fixes (mainly style and removing dead code)
Fix a bug in flatten_walk and add a test.
Fix a regression in tests (TaskManager) linked to the use of deferred_call.
Minor fix in debugger view.
Add  context menu to log display to allow to clear their content.
Fix a huge bug in Root Task preventing the correct update of the preferences.
Adding the possibility to re-enqueue a measure and clear processed measures.
Fix issues in task edition leading to wrong initial selection after loading.
Make textMonitor send window to front when restoring an existing window.