Barack and Michelle Obama are close to buying a massive Martha’s Vineyard estate. TMZ reports that the former president and first lady are in escrow — aka in contract to purchase — a 29-acre beachfront plot with a 6,892-square-foot main house. The Obamas were initially just renting the seven-bedroom, 8½-bathroom spread for summer 2019, but apparently loved it so much that they made an offer. It was most recently on the market asking $14.85 million, but the Obamas are apparently paying less. The property at 79 Turkeyland Cove Road in Edgartown, Mass. — owned by Boston Celtics chief Wyc Grousbeck...