Support updates introduced by doxygen 1.5.5

[anb0s]

Original Savannah ticket 5761 reported by None on Mon Feb 11 08:27:10 2008.

> Version 1.5.5 is available from subversion. > Here is the changelog w.r.t. the previous subversion update: > ------------------------------------------------------------------------------- > + CHG: id 493923: The options SOURCE_BROWSER, CALL_GRAPH, CALLER_GRAPH, > REFERENCES_RELATION, and REFERENCED_BY_RELATION can now be indepently > enabled and disabled. By default the relations are now disabled.

> Having checked out the updated code from subversion, I see that the new > SORT_GROUP_NAMES paremeter did make it into this release although it is > not mentioned here nor in the official changelog.