SEATTLE (Reuters) - Police are on the lookout for members of a machete-wielding gang in angry clown make-up after a rampage of robbery and violence that left nearly two dozen people injured in a park in western Washington state. The group, who said they were "juggalos," devotees of the Detroit-based rap-metal group Insane Clown Posse, attacked and robbed visitors to Fort Steilacoom Park while shouting "Woo, woo, juggalo!" to each other, according to court documents. Prosecutors in Pierce County south of Seattle charged three people with assault and robbery last week, but police in the City of Lakewood said they...