Implement CollaborationObjectCallGraph#merge(ExtractedStructure) ...

that uses lowestCommonAncestor.
Rename CollaborationAliasCollector#sortAliasListByTimeStamp() from
sort().
Add CollaborationObjectCallGraph#sortTracePointByTimeStamp()and test
file.

Implement CollaborationAliasCollector#merge(IAliasCollector). ...

Add CollaborationAliasCollectorTest and
CollaborationAliasCollector#sort(), Alias#getTimeStamp(), sample of
plural delta.