A A A Often successful music collaboration takes time to percolate. In the case of Glen Hansard and Marketa Irglova, aka the Swell Season, it has taken 16 years to reunite for the folk-flavored Forward. Echoing the Swell Season’s first two records, Forward features acoustic arrangements of lovely, secular hymns with the spare accompaniment of Hansard’s strummed guitar, Irglova’s piano, Marja Gaynor’s occasional strings, and Piero Perelli’s light percussion.