Add project files.

Beam.Exports/IAsyncExporter.cs

@@ -0,0 +1,10 @@
+namespace Beam.Exports {
+    public interface IAsyncExporter : IExporter {
+        /// <summary>
+        /// Asynchronously writes the object to the desired path, creating it if it does not exist.
+        /// </summary>
+        /// <param name="path">The path of the exported object</param>
+        /// <returns></returns>
+        public Task WriteAsync(string path);
+    }
+}