Move except into sorted position

Author: shivaram

R/pkg/NAMESPACE

@@ -99,6 +99,7 @@ exportClasses("DataFrame")
 exportMethods("columns",
               "distinct",
               "dtypes",
+              "except",
               "explain",
               "filter",
               "groupBy",
@@ -122,7 +123,6 @@ exportMethods("columns",
               "show",
               "showDF",
               "sortDF",
-              "except",
               "toJSON",
               "toRDD",
               "unionAll",