Rename to Octokit to be consistent with other API libs

GitHub is naming all of the libraries Octokit for their respective
platforms

Octokit.Reactive/Clients/ObservableUsersClient.cs

@@ -0,0 +1,32 @@
+using System;
+using System.Reactive.Threading.Tasks;
+
+namespace Octokit.Reactive.Clients
+{
+    public class ObservableUsersClient : IObservableUsersClient
+    {
+        readonly IUsersClient client;
+
+        public ObservableUsersClient(IUsersClient client)
+        {
+            Ensure.ArgumentNotNull(client, "client");
+
+            this.client = client;
+        }
+
+        public IObservable<User> Get(string login)
+        {
+            return client.Get(login).ToObservable();
+        }
+
+        public IObservable<User> Current()
+        {
+            return client.Current().ToObservable();
+        }
+
+        public IObservable<User> Update(UserUpdate user)
+        {
+            return client.Update(user).ToObservable();
+        }
+    }
+}