If device does not support double, returns immediately.
Double floating points are not default supported by OpenCL.
Merge pull request #1502 from melody-rain:2.4_Stereo_Match_Const_Space_BP
Merge pull request #1500 from alalek:fix_add_definitions
Merge pull request #1497 from jet47:fix-bug-3277
Update the OpenCL documents.
Merge pull request #1485 from vpisarev:ipp_fixes
fix three warning about mog, mog2 and KNearestNeighbour.
Merge pull request #1464 from StevenPuttemans:bugfix_3186_second
Merge remote-tracking branch 'upstream/master'
Removed trailing whitespaces
Merge pull request #1503 from ilya-lavrenov:ocl_arithm
Merge pull request #1470 from IceRage:min_enclosing_triangle
hortening the file names (HighDynamicRange -> HDR)
Merge remote-tracking branch 'upstream/master'
Docs updated, added InputArray, fixes for makePtr,...
Merge pull request #1511 from apavlenko:shorten_hdr
Replace obsolete Gtk symbols

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.
fix warning about addWeighted and remove magnitudeSqr().
pr #1464 reverted as breaking the build for Linux without libv4l library.
Merge pull request #1515 from asmorkalov:ocv_pr_1464_revert