use std::placeholders everywhere

before this was silently relying on boost placeholders, but those
default off now.

Author: Hello71

src/config.cc

@@ -488,7 +488,7 @@ namespace Astroid {
   void Config::merge_ptree(const ptree &pt)   {
     function<void(const ptree &,
       const ptree::path_type &,
-      const ptree&)> method = bind (&Config::merge, this, _1, _2, _3);
+      const ptree&)> method = bind (&Config::merge, this, std::placeholders::_1, std::placeholders::_2, std::placeholders::_3);
 
     traverse(pt, method);
   }

src/main_window.cc

@@ -260,52 +260,52 @@ namespace Astroid {
     keys.register_key ("M-1",
         "main_window.jump_to_page_1",
         "Jump to page 1",
-        bind (&MainWindow::jump_to_page, this, _1, 1));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 1));
 
     keys.register_key ("M-2",
         "main_window.jump_to_page_2",
         "Jump to page 2",
-        bind (&MainWindow::jump_to_page, this, _1, 2));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 2));
 
     keys.register_key ("M-3",
         "main_window.jump_to_page_3",
         "Jump to page 3",
-        bind (&MainWindow::jump_to_page, this, _1, 3));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 3));
 
     keys.register_key ("M-4",
         "main_window.jump_to_page_4",
         "Jump to page 4",
-        bind (&MainWindow::jump_to_page, this, _1, 4));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 4));
 
     keys.register_key ("M-5",
         "main_window.jump_to_page_5",
         "Jump to page 5",
-        bind (&MainWindow::jump_to_page, this, _1, 5));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 5));
 
     keys.register_key ("M-6",
         "main_window.jump_to_page_6",
         "Jump to page 6",
-        bind (&MainWindow::jump_to_page, this, _1, 6));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 6));
 
     keys.register_key ("M-7",
         "main_window.jump_to_page_7",
         "Jump to page 7",
-        bind (&MainWindow::jump_to_page, this, _1, 7));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 7));
 
     keys.register_key ("M-8",
         "main_window.jump_to_page_8",
         "Jump to page 8",
-        bind (&MainWindow::jump_to_page, this, _1, 8));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 8));
 
     keys.register_key ("M-9",
         "main_window.jump_to_page_9",
         "Jump to page 9",
-        bind (&MainWindow::jump_to_page, this, _1, 9));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 9));
 
     keys.register_key ("M-0",
         "main_window.jump_to_page_0",
         "Jump to page 0",
-        bind (&MainWindow::jump_to_page, this, _1, 0));
+        bind (&MainWindow::jump_to_page, this, std::placeholders::_1, 0));
 
     keys.register_key ("C-w", "main_window.close_page",
         "Close mode (or window if other windows are open)",

src/modes/keybindings.cc

@@ -561,7 +561,7 @@ namespace Astroid {
       register_key (b->first,
                     b->first.name,
                     ustring::compose ("Run hook: %1,%2", b->second.first, b->second.second),
-                    bind (cb, _1, b->second.first, b->second.second)
+                    bind (cb, std::placeholders::_1, b->second.first, b->second.second)
                     );
 
       b++;

src/modes/thread_index/thread_index_list_view.cc

@@ -477,38 +477,38 @@ namespace Astroid {
     multi_keys.register_key ("N",
                              "thread_index.multi.mark_unread",
                              "Toggle unread",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MUnread, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MUnread, std::placeholders::_1));
 
     multi_keys.register_key ("*",
                              "thread_index.multi.flag",
                              "Toggle flagged",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MFlag, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MFlag, std::placeholders::_1));
 
     multi_keys.register_key ("a",
                              "thread_index.multi.archive",
                              "Toggle archive",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MArchive, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MArchive, std::placeholders::_1));
 
     multi_keys.register_key ("S",
                              "thread_index.multi.mark_spam",
                              "Toggle spam",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MSpam, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MSpam, std::placeholders::_1));
 
     multi_keys.register_key ("+",
                              "thread_index.multi.tag",
                              "Tag",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MTag, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MTag, std::placeholders::_1));
 
 
     multi_keys.register_key ("C-m",
                              "thread_index.multi.mute",
                              "Toggle mute",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MMute, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MMute, std::placeholders::_1));
 
     multi_keys.register_key ("t",
                              "thread_index.multi.toggle",
                              "Toggle marked",
-                             bind (&ThreadIndexListView::multi_key_handler, this, MToggle, _1));
+                             bind (&ThreadIndexListView::multi_key_handler, this, MToggle, std::placeholders::_1));
 
     keys->register_key (Key (GDK_KEY_semicolon),
           "thread_index.multi",