Force Elixir namespace for compile-time List.flatten/1 calls. Relates to #256

Author: kipcole9

lib/cldr/timezone.ex

@@ -26,7 +26,7 @@ defmodule Cldr.Timezone do
                            end)
                            |> Enum.map(fn {k, v} ->
                              case Cldr.validate_territory(k) do
-                               {:ok, territory} -> {territory, List.flatten(v)}
+                               {:ok, territory} -> {territory, Elixir.List.flatten(v)}
                                {:error, _} -> nil
                              end
                            end)

lib/cldr/validity/u.ex

@@ -115,7 +115,7 @@ defmodule Cldr.Validity.U do
         {k, nil} -> {String.to_atom(k), k}
         {k, v} -> {String.to_atom(v), k}
       end)
-      |> List.flatten()
+      |> Elixir.List.flatten()
       |> Map.new()
 
     defp encode_key(unquote(key), value) when value in unquote(Map.keys(inverted_values)) do