She sings “old modal folk songs” with Solas one week and performs with the indie band tUnE-yArDs the next. You might catch her with her own group as they re-imagine the piano miniatures of Bartók, or at a choir rehearsal of her original choral compositions. Musical improviser and experimenter Moira Smiley returns to “Musician’s Spotlight” on the heels of her latest release, “Unzip The Horizon.” About it, she says: “The lonesome freedom and experience of years on tour were midwife to this music,