When Roger Hodgson stepped out on stage last night to launch the next leg of his Solo Tramp world tour, he did so in support of the Northern California Center for the Arts and with the backing of a Macintosh application from Galleon Software. Perhaps best known from his days as lead singer of the British rock group Supertramp, Hodgson now takes his breakfast in America and graciously offered to perform a special home-town concert to benefit the arts center located in Grass Valley, about fifty miles northeast of Sacramento.