National Public Radio: After spending years as a political football in the U.S., the Keystone XL pipeline's would-be builder is now asking for a timeout in the review process. Why now? Changing politics in the U.S. and Canada, falling oil prices and mounting pressure from environmentalists have marked a turnaround for the company, which had pushed for approval of the project, and its supporters. Here are five things to know about where the pipeline stands now: 1. Geography gives the U.S. government a say The United...