[libsigcplusplus] signal_emit: Make call_type private and remove iterator_type.

[Murray Cumming <murrayc src gnome org>]

commit 08d916d9c28da394f292286f867d6ed51e14df41
Author: Murray Cumming <murrayc murrayc com>
Date:   Fri Apr 15 10:37:10 2016 +0200

    signal_emit: Make call_type private and remove iterator_type.

 sigc++/signal.h |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/sigc++/signal.h b/sigc++/signal.h
index dcd408a..56de251 100644
--- a/sigc++/signal.h
+++ b/sigc++/signal.h
@@ -678,11 +678,12 @@ private:
 template <class T_return, class... T_arg>
 struct signal_emit<T_return, void, T_arg...>
 {
-  using self_type = signal_emit<T_return, void, T_arg...>;
+private:
   using slot_type = slot<T_return(T_arg...)>;
-  using iterator_type = signal_impl::const_iterator_type;
   using call_type = typename slot_type::call_type;
 
+public:
+
   /** Executes a list of slots.
    * The arguments are passed directly on to the slots.
    * The return value of the last slot invoked is returned.
@@ -783,11 +784,12 @@ struct signal_emit<T_return, void, T_arg...>
 template <class... T_arg>
 struct signal_emit<void, void, T_arg...>
 {
-  using self_type = signal_emit<void, void, T_arg...>;
+private:
   using slot_type = slot<void(T_arg...)>;
-  using iterator_type = signal_impl::const_iterator_type;
   using call_type = typename slot_type::call_type;
 
+public:
+
   /** Executes a list of slots using an accumulator of type @e T_accumulator.   * The arguments are
    * passed directly on to the slots.
    * @param _A_a Arguments to be passed on to the slots.