gtk/src/filelist.am: Move alignment.hg to gtkmm_files_deprecated_hg
Gtk::Button: Deprecate the alignment API which is deprecated in GTK+

* gtk/src/button.hg: Deprecate set_alignment(), get_alignment(),
property_xalign() and property_yalign(), which are deprecated in GTK+.
Gtk::Container, Widget: Deprecate API which is deprecated in GTK+

* gtk/src/container.hg: Deprecate [set|get]_resize_mode(),
set_reallocate_redraws().
* gtk/src/widget.hg: Deprecate reparent(), region_intersect(),
get_root_window(), [set|get]_margin_[left|right](), property_style(),
property_margin_[left|right]().
property_style() should perhaps be deleted, although that would break API and
ABI. It can't be used because it requires the non-existent Gtk::Style class.