Robert Mason Co. is closing. The Short North office products and lifestyle shop, as well as its online presence, is liquidating and will be closed by the end of May, founder and owner Robert Grimmett said in a release Tuesday. "Sadly this was not a result of poor performance, it was a product of cash flow constraints and debt resulting from the 2014 fire that destroyed the Gay Street Columbus store," he said, further citing "substantial debt and legacy issues caused by the fire." "Losing...