No changes, just use symbolic NO_IMAGE constant instead of -1 or wxNOT_FOUND.

Existing declarations used -1 in several places to indicate the absence of the
image which wasn't especially clear and was also inconsistent with other
places that used wxNOT_FOUND which didn't make much sense in this context.

Add a new symbolic constant NO_IMAGE in wxWithImages and use it in the classes
deriving from it. This still doesn't help with wx{Tree,List}Ctrl but improves
clarity for the other classes.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68810 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/bookctrl.h

@@ -181,7 +181,7 @@ public:
     virtual bool AddPage(wxWindow *page,
                          const wxString& text,
                          bool bSelect = false,
-                         int imageId = -1)
+                         int imageId = NO_IMAGE)
     {
         DoInvalidateBestSize();
         return InsertPage(GetPageCount(), page, text, bSelect, imageId);
@@ -192,7 +192,7 @@ public:
                             wxWindow *page,
                             const wxString& text,
                             bool bSelect = false,
-                            int imageId = -1) = 0;
+                            int imageId = NO_IMAGE) = 0;
 
     // set the currently selected page, return the index of the previously
     // selected one (or wxNOT_FOUND on error)