[WIP] Add repository traffic preview (#1457)

* Add response models

* Supress message

* correct spelling Timestamp

* implement traffic client

* add reactive client

* [WIP] unit tests

* add argument check

* finish unit tests

* add integration tests

* Change repositoryId from int to long
Remove GetAll naming of endpoints and add to PaginationTest exclusions
Rename View and Clone classes to be more specific
Add handling of TimeStamp fields being UtcUnix time
Add integration tests for repositoryId methods

Octokit.Reactive/Clients/ObservableRepositoriesClient.cs

@@ -36,6 +36,7 @@ namespace Octokit.Reactive
             Merging = new ObservableMergingClient(client);
             Page = new ObservableRepositoryPagesClient(client);
             Invitation = new ObservableRepositoryInvitationsClient(client);
+            Traffic = new ObservableRepositoryTrafficClient(client);
         }
 
         /// <summary>
@@ -880,6 +881,14 @@ namespace Octokit.Reactive
         /// <remarks>
         /// See the <a href="https://developer.github.com/v3/repos/invitations/">Repository Invitations API documentation</a> for more information.
         /// </remarks>
-        public IObservableRepositoryInvitationsClient Invitation { get; private set; }        
+        public IObservableRepositoryInvitationsClient Invitation { get; private set; }
+
+        /// <summary>
+        /// Access GitHub's Repository Traffic API
+        /// </summary>
+        /// <remarks>
+        /// Refer to the API documentation for more information: https://developer.github.com/v3/repos/traffic/
+        /// </remarks>
+        public IObservableRepositoryTrafficClient Traffic { get; private set; }
     }
 }