#4389: Annotate in dirTreeView, #4764: fixed

#4389:
- Subclassed QFileSystemModel, added one column and connected it to
GraphModel
- When you edit annotation you add element to model, but set flag
isShown to false (in QMap), so that it is not shown on scene neither in
tableView. It is processed by MainWindow because it affects lots of
widgets.
- Set correct header data for tableView and SourceBrowser
#4764:
- Not proper cast of object, used Node class, but needed ObjectVisual +
check if they are links (because links don't have real polygon to
intersect with)
Also:
- When object added, it is also affected by filter immediately(on scene)
- Saving annotation while converting textblock/identifier
- Now converter saves links of object, not model
- When holding Ctrl and clicking on object we move to it in other views