0029674: Improvements in Inspector tool

- preferences for dock windows geometry, tree view columns and current view projection;
- ViewControl package for common functionality between plugins;
- processing Location and Orientation for external TopoDS_Shape object
- 'F5' key to update content of each plugin
- visibility column in tree view (used now only in ShapeView)
- properties child item for context (presents tree of current Filters of context)

tools/DFBrowser/DFBrowser_TreeModel.hxx

@@ -95,11 +95,10 @@ public:
   Standard_EXPORT virtual QVariant data (const QModelIndex& theIndex,
                                          int theRole = Qt::DisplayRole) const Standard_OVERRIDE;
 
-  //! Returns count of columns in the model
-  //! \param theParent an index of the parent item
-  //! \return integer value
-  virtual int columnCount (const QModelIndex& theParent = QModelIndex()) const Standard_OVERRIDE
-  { (void)theParent; return 1; }
+protected:
+  //! Creates root item
+  //! \param theColumnId index of a column
+  virtual void createRootItem (const int theColumnId);
 
 private: