Update to Doxygen 1.8.8 (the same version currently used by wxWidgets)

build.py

@@ -68,11 +68,11 @@ sipMD5 = {
 wafCurrentVersion = '1.7.15-p1'
 wafMD5 = 'e44003373c965f4221bbdc4c9b846128'
 
-doxygenCurrentVersion = '1.8.2'
+doxygenCurrentVersion = '1.8.8'
 doxygenMD5 = {
-    'darwin' : '96a3012d97893f4e05387cda544de0e8',
-    'win32'  : '71f97ebaa87171c824a7742de5bf3381', 
-    'linux'  : '6fca3d2016f8019a7737716eee4d5377', 
+    'darwin' : '71c590e6cab47100f23919a2696cc7fd',
+    'win32'  : 'a3dcff227458e423c132f16f57e26510', 
+    'linux'  : '083b3d8f614b538696041c7364e0f334', 
 }
 
 # And the location where they can be downloaded from

etgtools/sphinx_generator.py

@@ -582,7 +582,8 @@ class ParameterList(Node):
         name = xml_item.name or xml_item.pyName
         name = RemoveWxPrefix(name)
 
-        is_overload = self.GetTopLevelParent().is_overload
+        parent = self.GetTopLevelParent()
+        is_overload = parent.is_overload if parent else False
         
         if xml_item.overloads and not is_overload:
             return