Some groups leaven melancholy with change-of-mood rhapsody; Mad Agnes reverses the formula. Margo Hennebach, Adrienne Jones and Mark Saunders know that life’s road is full of bumps, but celebrate the indefatigable determination to move on. Songs about lessons learned from chocolate, the moon and dogs could cross the border between sweetness and treacle. But these are balanced by darker material such as “Black Crow,” which admits that sorrow is hard to shoo away, and “Make It Better,” which recognizes sadness as part of the healing process. Add to this diverse repertoire three-part harmonies as tight as jeans from the dryer and you’d be crazy not to check out Mad Agnes.