Repository Commits Get All

Added the logic for getting all commits for a repository including unit
tests and XML docs

Octokit.Reactive/Clients/IObservableRepositoryCommitsClients.cs

@@ -15,5 +15,13 @@ namespace Octokit.Reactive
         /// <returns></returns>
         [SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "base")]
         IObservable<CompareResult> Compare(string owner, string name, string @base, string @head);
+
+        /// <summary>
+        /// Gets all commits for a given repository
+        /// </summary>
+        /// <param name="owner">The owner of the repository</param>
+        /// <param name="name">The name of the repository</param>
+        /// <returns></returns>
+        IObservable<GitHubCommit> GetAll(string owner, string name);
     }
 }