This isn't your parent's MGM.In discussing the extent of renovations at the Grand Sierra Resort, Reno's largest hotel property at 2,000 rooms, it's easier to list what hasn't been upgraded the theater, box office ticket counter and sports book area than what has.New owners the Meruelo Group have sunk more than $25 million into the GSR to bring the hotel at Mill and East Second streets up to today's standards and recapture market share lost to competing top-tier hotel-casino properties in the area. Mereulo Group, headed by Alex Meruelo, took over ownership of the Grand Sierra in April of 2011.The …