0030507: Visualization - introduce AIS_ViewController

ViewerTest_EventManager now inherits AIS_ViewController.
Platform-dependent user input handling within ViewerTest has been revised
to process events in common way through AIS_ViewController.
The mouse navigation has been changed, so that left mouse clicked
without modifers now rotates View.
The rubber-band selection can be activated via Alt+LeftMouseButton.
Selection is now done on mouse unclick and keyboard short-cuts take effect on unclick.

Aspect_Window::SetTitle() - added new method configuring Window title.
Introduced new types Aspect_Touch, Aspect_VKey, Aspect_ScrollDelta
for processing window events in platform-independent way.

src/AIS/AIS_InteractiveContext.hxx

@@ -557,6 +557,14 @@ public: //! @name Selection management
   Standard_EXPORT void AddOrRemoveSelected (const Handle(AIS_InteractiveObject)& theObject,
                                             const Standard_Boolean               theToUpdateViewer);
 
+  //! Updates Selected state of specified owner without calling HilightSelected().
+  //! Has no effect if Selected state is not changed, and redirects to AddOrRemoveSelected() otherwise.
+  //! @param theOwner owner object to set selected state
+  //! @param theIsSelected new selected state
+  //! @return TRUE if Selected state has been changed
+  Standard_EXPORT Standard_Boolean SetSelectedState (const Handle(SelectMgr_EntityOwner)& theOwner,
+                                                     const Standard_Boolean               theIsSelected);
+
   //! Highlights selected objects.
   Standard_EXPORT void HilightSelected (const Standard_Boolean theToUpdateViewer);
 
@@ -816,6 +824,9 @@ public: //! @name common properties
   //! returns the number of removed  structures from the viewers.
   Standard_EXPORT Standard_Integer PurgeDisplay();
 
+  //! Return rotation gravity point.
+  Standard_EXPORT virtual gp_Pnt GravityPoint (const Handle(V3d_View)& theView) const;
+
 public: //! @name debug visualization
 
   //! Visualization of sensitives - for debugging purposes!