It is Saturday afternoon at Jamaica Pond. Music is pumping, the growing crowd is dancing, and Yoshi Walsh is taking a dive. Not into the water, but into his audience; a large collection of Bostonians who have ventured to see his band, Streight Angular, play at the fifth annual Jamaica Plain Music Festival. Walsh, a colorful Pennsylvania native who currently resides in Jamaica Plain, has always been a free spirit, but found a specific love and sense of freedom in making music. Starting his artistic career during a brief stint in college, Walsh spent most of his free time practicing painting, writing poetry and teaching himself guitar.