Switch to using DI to acquire Node instances. Bump versions to alpha2.

Microsoft.AspNet.NodeServices/Configuration.cs

@@ -0,0 +1,24 @@
+using Microsoft.Framework.DependencyInjection;
+
+namespace Microsoft.AspNet.NodeServices {
+    public static class Configuration {
+        public static void AddNodeServices(this IServiceCollection serviceCollection, NodeHostingModel hostingModel = NodeHostingModel.Http) {
+            serviceCollection.AddSingleton(typeof(INodeServices), (serviceProvider) => {
+                return CreateNodeServices(hostingModel);
+            });
+        }
+
+        private static INodeServices CreateNodeServices(NodeHostingModel hostingModel)
+        {
+            switch (hostingModel)
+            {
+                case NodeHostingModel.Http:
+                    return new HttpNodeInstance();
+                case NodeHostingModel.InputOutputStream:
+                    return new InputOutputStreamNodeInstance();
+                default:
+                    throw new System.ArgumentException("Unknown hosting model: " + hostingModel.ToString());
+            }
+        }
+    }
+}