A bona fide fire cracker, Mandy has an tow sack of original tunes in the folk-goes-pop arena but can also bring out a full arsenal of cover material. Make no mistake, though: Rowden is hardly just another “chick songwriter.” She’s funny as hell, first off, and versatile enough to play an ever-expanding list of instruments that now includes piano, fiddle, mandolin, bass, harmonica, drums, ukulele, and banjo. (And according to one Texas critic, “When she plays the fiddle, hearts melt.”)…