Encapsulate wxPGProperty::m_children member variable.

Implement RemoveChild and SortChildren methods to perform operations on m_children member variable.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78428 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/propgrid/property.h

@@ -2427,6 +2427,12 @@ protected:
     // Removes child property with given pointer. Does not delete it.
     void RemoveChild( wxPGProperty* p );
 
+    // Removes child property at given index. Does not delete it.
+    void RemoveChild(unsigned int index);
+
+    // Sorts children using specified comparison function.
+    void SortChildren(int (*fCmp)(wxPGProperty**, wxPGProperty**));
+
     void DoEnable( bool enable );
 
     void DoPreAddChild( int index, wxPGProperty* prop );