Log Message:
Changes 2.18.2:
* Reintroduce accidentally removed API methods Gtk::Widget::can_default()
  and Gtk::Widget::can_focus().
* Include infobar.h from main gtkmm.h header.

Changes 2.18.1:
* RecentManager: Undeprecate get_default().

Changes 2.18.0:
* Clipboard: wait_for_targets): Fix a crash.
Build:
* Require a recent pangomm.
* Style: Fix a compiler error with the Intel C++ compiler.
* Fix recently-introduced problems with disable-deprecated options.