[regexxer] (14 commits) ...Require even newer gtkmm that uses C++11.

[Murray Cumming <murrayc src gnome org>]

Summary of changes:

  4df23fd... Use C++11, needed by newer gtkmm. (*)
  0984a7e... FileBuffer: Replace deprecated begins_tag(). (*)
  7e77d56... Replace (deprecated) Gdk::Color with Gdk::RGBA. (*)
  f1063aa... Replace use of (deprecated) Gtk::Stock icons. (*)
  84c9b5f... Replace all (deprecated) auto_ptr with unique_ptr. (*)
  b2accb4... MainWindow: Replace (deprecated) stock button names. (*)
  4fb5cc4... Replace (deprecated) get_vbox(). (*)
  95cdf58... Avoid missing initializer compiler warnings. (*)
  2bdbd6a... Replace use of deprecated Gtk::Label constructor. (*)
  16ed75d... Replace use of deprecated Misc::get/set_padding(). (*)
  e4eaded... Remove registering of new (deprecated) stock item for save- (*)
  49f0f1b... Replace use of (deprecated) Gtk::Application::add_accelerat (*)
  53f5614... Require a newer gtkmm because we use newer API. (*)
  28ae251... Require even newer gtkmm that uses C++11. (*)

(*) This commit already existed in another branch; no separate mail sent