The second parameter of gtk_widget_set_realized is of type gboolean
(gint). This is to ensure compatibility on alternative compilers and
platforms.

This update replaces depreciated Gtk1.x symbols with Gtk2.x symbols in
preparation for adding Gtk3 support. These edits aim to be fully
compatible with Gtk2.x, allowing backward compatibility.

The following symbols have been replaced in this commit:

Gtk symbols that have been moved to the Gdk library:
 - GtkType -> Gtype
 - GTK_CHECK_CAST -> G_TYPE_CHECK_INSTANCE_CAST
 - GTK_CHECK_TYPE -> G_TYPE_CHECK_INSTANCE_TYPE
 - gtk_signal_connect -> g_signal_connect
 - GTK_SIGNAL_FUNC -> G_CALLBACK
 - gtk_type_class -> g_type_class_peek
 - gtk_type_new-> g_object_new
 - GtkTypeInfo -> GtypeInfo (Not required for
   g_type_register_static_simple)
 - gtk_type_unique -> g_type_register_static_simple
 - gdk_draw_image_rgb -> replaced by gdk_cairo_source_pixbuf
   NB: This requires porting to use cairo contexts and GdkPixbufs.

The following gtk symbols are changed for their modern equivalent:
 - GTK_WIDGET_REALIZED -> gtk_widget_get_realized
 - GTK_OBJECT_FLAGS -> gtk_widget_set_realized

Symbols without replacement:
 - gtk_range_set_update_policy -> No replacement; as default policy is
   set to continuous we can delete this line.

Conflicts:
	.gitignore
	doc/tutorials/objdetect/cascade_classifier/cascade_classifier.rst
	modules/gpu/src/match_template.cpp
	modules/imgproc/include/opencv2/imgproc/imgproc.hpp
	modules/ocl/include/opencv2/ocl/ocl.hpp
	modules/ocl/perf/perf_precomp.hpp

Previously we incorrectly assumed data was aligned in 16 bytes, which should be 32.

it conflicts with cv::detail

changed default parameters in CreateERFiltersNM{1,2} functions. They are not needed now in the sample example.

begin_x[1] is not the second component of the element, but the element
after the one pointed to begin_x. When begin_x points to the last
element, that line overwrites data past the end of the allocation, which,
during my tests, happened to contain the reference count for the matrix.
Hilarity ensues.