Recreates the entries master list based on the groups hierarchy (order matters here,
        since the parser uses order to determine lineage).

def _rebuild_entries(self):
        """
        Recreates the entries master list based on the groups hierarchy (order matters here,
        since the parser uses order to determine lineage).
        """
        self.entries = []
        def collapse_entries(group):
            for entry in group.entries:
                self.entries.append(entry)
            for subgroup in group.children:
                collapse_entries(subgroup)
                
        collapse_entries(self.root)