Added list_dbIDs method.

modules/Bio/EnsEMBL/DBSQL/DnaAlignFeatureAdaptor.pm

@@ -293,7 +293,23 @@ sub _objs_from_sth {
   return \@features;
 }
 
-    
+=head2 list_dbIDs
+
+  Arg [1]    : none
+  Example    : @feature_ids = @{$dna_align_feature_adaptor->list_dbIDs()};
+  Description: Gets an array of internal ids for all dna align features in the current db
+  Returntype : list of ints
+  Exceptions : none
+  Caller     : ?
+
+=cut
+
+sub list_dbIDs {
+   my ($self) = @_;
+
+   return $self->_list_dbIDs("dna_align_feature");
+}
+
 1;