ISLAMABAD, Pakistan (Reuters) - A Chinese engineer held hostage by al Qaeda-linked militants in Pakistan was killed on Thursday but his colleague rescued in a commando assault that killed their five kidnappers, officials said. Chinese engineers Wang Ende and Wang Peng were heading to work on a dam project in the remote South Waziristan tribal region when they were kidnapped on Saturday by Uzbek and Pakistani militants led by a former Guantanamo Bay detainee. Wang Peng, who had worked as a surveyor on the project, was critically hurt by gunfire from the kidnappers and later died, said Pakistani military spokesman...