Add IOptionsAccessor as a default service

src/Microsoft.AspNet.Hosting/HostingServices.cs

@@ -59,6 +59,14 @@ namespace Microsoft.AspNet.Hosting
                 Lifecycle = LifecycleKind.Scoped
             };
 
+            // TODO: Review whether this is the right long term home, and whether Scoped is correct lifetime
+            yield return new ServiceDescriptor
+            {
+                ServiceType = typeof(IOptionsAccessor<>),
+                ImplementationType = typeof(OptionsAccessor<>),
+                Lifecycle = LifecycleKind.Scoped
+            };
+
             if (PlatformHelper.IsMono)
             {
 #if NET45