ERWIN — There’s a new restaurant coming to Erwin. The pounding of hammers and whir of power tools heard along the 100 block of South Main Avenue in recent weeks is a prelude to the banter of hungry customers who will soon be coming downtown to eat. Jason and Julie Gilliland, owners of Site Design Studio in nearby Weaverville, N.C., are renovating the former Main Street Mall building with plans to bring a family eatery to the lower level and a couple of loft apartments upstairs. Their intention, Jason said, is to “attract an existing restaurant that may be looking for a second location.” They have already begun conversations with some successful eateries in Weaverville.