The recent massacre of civilian workers by separatist rebels in Indonesia's restive Papua province has cast a spotlight on one of the world's longest-running insurgencies, with no end to the bloody conflict in sight.The killings are a marked escalation from decades of mostly sporadic skirmishes between poorly armed and disorganised guerrillas and a powerful Indonesian military accused of gross human rights abuses against civilians.Some 16 employees of a state-owned contractor were m