Moved stable tool tip concept into the BToolManager class.

* This removes the fVisibleToolTip member from BView, and fixes bug #5669;
  BToolTipManager::ShowTip() now gets the owner of the tool tip as an extra
  parameter.
* Removed the work-around to hide that bug.
* Improved ToolTipTest application to include more test cases like a view that
  periodically update its tool tip via SetToolTip(const char*), and one that
  sets a new tool tip every second.
* Furthermore, added a test that shows that inner views inherit the tool tip
  of their parents.
* Fixed another bug in BToolTipManager::ShowTip() that would release an
  extra reference to the tool tip currently shown.

headers/private/interface/ToolTipWindow.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009, Haiku, Inc. All Rights Reserved.
+ * Copyright 2009-2012, Haiku, Inc. All Rights Reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef TOOL_TIP_WINDOW_H
@@ -11,13 +11,19 @@
 
 namespace BPrivate {
 
+
 class ToolTipWindow : public BWindow {
 public:
-							ToolTipWindow(BToolTip* tip, BPoint where);
+							ToolTipWindow(BToolTip* tip, BPoint where,
+								void* owner);
 
 	virtual	void			MessageReceived(BMessage* message);
+
+private:
+			void*			fOwner;
 };
 
+
 }	// namespace BPrivate