Brunei's all-powerful sultan will mark 50 years on the throne Thursday with lavish celebrations including a glittering procession, a 21-gun salute and a ceremony at his vast, golden-domed palace.The festivities for Sultan Hassanal Bolkiah – which will include the monarch being carried past huge crowds of well-wishers in a chariot – are the centrepiece of events to mark his golden jubilee.The 71-year-old, the world's second-longest reigning monarch, ascended to the throne of the tiny