General Motors has put six of its cars under review, including its once breakthrough Chevrolet Volt plug-in hybrid, and is evaluating whether to cancel them in the coming years, according to a report from Reuters. The news comes as sales of cars continue to plummet in the U.S. and as consumers increasingly turn to SUVs and pickups. Besides the Chevrolet Volt hybrid, other vehicles believed to be under consideration for elimination iinclude the Buick LaCrosse, Cadillac CT6, Cadillac XTS, Chevrolet Impala and Chevrolet Sonic, according to Reuters. GM spokesman Jim Cain declined to comment on the report. UAW President Dennis...