parse secondary structure from locarna clustalw style RNA alignments

LocaRNA produces clustalW style alignments where RNA secondary structures (consensus and parsimonious) are shown where ClustalW would normally report the consensus line for each column. e.g.:

                   ..............((((...(((......)))......))))..........................((((((((....))))))))...............................
ABJJ01000011_1_2 CGCUCAUCCAGAG-GGGCAGAGGGAUACGGCCCGAUGAAGCCCCGGCAACCCUCCAGUCGGUUCUCGUAG-CGAUCGCUGACGAUCGUCUCCGCGAGGCUCCCGACUCGGGAAGGUGCCA
..
..

AP006627_1_15635 CUCUUAUAACGAG-AAGCGGAGGGACUG-GCCCAAUGAAGCUUCAGCAAC-------------------CAUUCAU--UGCGAUGAAAA-----------------------GGUGCUAA
                   ..............((((...(((......)))......)))).......-------------------((((((((....))))))))----------------------.........