Replace g_idle_add/g_timeout_add with their gdk_threads counterparts

Replace g_idle_add/g_timeout_add with their gdk_threads counterparts

* examples/hildon-hvolumebar-timer-example.c
(on_idle, main)
* hildon/hildon-banner.c
(hildon_banner_timeout, hildon_banner_ensure_timeout)
* hildon/hildon-calendar.c
(calendar_timer, start_spinning)
* hildon/hildon-color-chooser.c
(inline_limited_expose)
* hildon/hildon-date-editor.c
(hildon_date_editor_entry_focus_in)
(hildon_date_editor_entry_validate)
(hildon_date_editor_entry_select_all)
* hildon/hildon-note.c
(on_show_cb)
* hildon/hildon-number-editor.c
(hildon_number_editor_button_pressed)
(hildon_number_editor_start_timer, do_mouse_timeout),
(add_select_all_idle, hildon_number_editor_select_all)
* hildon/hildon-time-editor.c
(hildon_time_editor_entry_focus_in)
(highlight_callback, hildon_time_editor_validate)
(hildon_time_editor_entry_select_all)
* hildon/hildon-time-picker.c
(hildon_time_picker_arrow_press)
(hildon_time_picker_key_repeat_timeout)
* hildon/hildon-window.c
(hildon_window_key_press_event)
(hildon_window_escape_timeout):
Replace all calls to g_idle_add/g_timeout_add with their
gdk_threads counterparts.

Fixes: NB#126198 (gdk-threads API should be used to install idle
and timeout handlers)