About 20 downtown Bangor businesses have been told to leave their 27 State St. building after a New York real estate development group bought the property and announced its intent to renovate it. The group, led by New York-based developer Dash Davidson, bought the historic downtown Bangor building last week for $975,000, according to property records. In a letter sent to tenants on Friday informing them of the sale, the company said it “intends to fully renovate the entire building in accordance with a historic rehabilitation.