Wila Frank Black Cloud Tone Tree Music   Singer-songwriter Wila Frank’s debut LP Black Cloud defies the expectations of a Music City artist. Like a number of musicians who have moved to Nashville in the wake of the city’s big boom, Frank isn’t a country artist. Her work hews closer to indie rock, with fetching quirks that make it distinctive. For instance, there is a repeated sharp fourth that gives the progression in “Oh Fate” an unconventional tinge.   Frank’s singing sometimes adopts a disaffected, even laconic, tone, which makes the soaring climaxes of songs such as “Fire” even more