Replace long with int

Turns out that we store these values as int(11) in MySql.
The 11 is irrelevant and pertains to display. int is a 4 byte
(aka 32 bit) integer. So this maps to a .NET Int32 (aka int).

While changing keeping it long might be future proofing, it also
requires changes to GHfW and I figure let's jump that hurdle
when we get there.

Octokit.Reactive/IObservableAuthorizationsClient.cs

@@ -12,9 +12,9 @@ namespace Octokit.Reactive
         IObservable<IReadOnlyCollection<Authorization>> GetAll();
         [SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "Get",
             Justification = "It's fiiiine. It's fine. Trust us.")]
-        IObservable<Authorization> Get(long id);
-        IObservable<Authorization> Update(long id, AuthorizationUpdate authorization);
+        IObservable<Authorization> Get(int id);
+        IObservable<Authorization> Update(int id, AuthorizationUpdate authorization);
         IObservable<Authorization> Create(AuthorizationUpdate authorization);
-        IObservable<Unit> Delete(long id);
+        IObservable<Unit> Delete(int id);
     }
 }