- ICultureSelector to set current request culture.

- Default implementation uses site setting with a low priority.
- Tests.

--HG--
branch : dev

src/Orchard.Web/Modules/Orchard.Setup/SetupMode.cs

@@ -123,6 +123,11 @@ namespace Orchard.Setup {
                 get { return ""; }
                 set { throw new NotImplementedException(); }
             }
+
+            public string SiteCulture {
+                get { return ""; }
+                set { throw new NotImplementedException(); }
+            }
         }
     }
 }