Added support for nested classes in Doxygen groups

doxygen/Doxyfile

@@ -348,7 +348,7 @@ DISTRIBUTE_GROUP_DOC   = NO
 # is disabled and one has to add nested compounds explicitly via \ingroup.
 # The default value is: NO.
 
-GROUP_NESTED_COMPOUNDS = NO
+GROUP_NESTED_COMPOUNDS = YES
 
 # Set the SUBGROUPING tag to YES to allow class member groups of the same type
 # (for instance a group of public functions) to be put as a subgroup of that