gdk3: remove trailing spaces
gdk3: add Init_gdk_device_manager() default declaration
gdk3: add macro to treat GDK object
gdk3 rbgtk.c: cleanup warning and add declaration Init_gdk_device_manager
gdk3: implement Gdk::Device#get_position and Gdk::Device#warp Gdk::Device#grab
gdk3: implement Gdk::Window#get_device_position
gdk3 rbgdkdisplay.c: cleanup deprecation warning
gdk3: cleanup deprecation warning
gdk3: add deprecation methods to deprecated.rb
gtk3: cleanup deprecation warning
gtk3: remove trailing spaces
gtk3: add deprecation methods to deprecated.rb