The audience applauds. The band jumps into a song, and then Mary Stallings effortlessly joins in. "I love the east, I love the west," she sings in a voice that's as warm and true as a convertible ride through the heart of spring. "I love the north and south, they're the best, only go there as a guest, cause I love being here with you." More than just the opening of Stallings' latest CD "Live at the Village Vanguard," it's a fitting declaration from a critically acclaimed singer, who's b …