edit-dialog: move bindings to UI file

We don't need to manually bind these properties in
the source code if we can make it on the UI files.

data/ui/edit-dialog.ui

@@ -15,6 +15,7 @@
     <child type="titlebar">
       <object class="GtkHeaderBar" id="titlebar">
         <property name="visible">True</property>
+        <property name="title" bind-source="summary_entry" bind-property="text" bind-flags="default" />
         <child>
           <object class="GtkButton" id="cancel_button">
             <property name="label" translatable="yes">Cancel</property>
@@ -232,6 +233,7 @@
                   <object class="GcalTimeSelector" id="start_time_selector">
                     <property name="visible">True</property>
                     <property name="can_focus">True</property>
+                    <property name="sensitive" bind-source="all_day_check" bind-property="active" bind-flags="invert-boolean|default" />
                     <signal name="modified" handler="update_time" object="GcalEditDialog" swapped="no"/>
                   </object>
                   <packing>
@@ -266,6 +268,7 @@
                   <object class="GcalTimeSelector" id="end_time_selector">
                     <property name="visible">True</property>
                     <property name="can_focus">True</property>
+                    <property name="sensitive" bind-source="all_day_check" bind-property="active" bind-flags="invert-boolean|default" />
                     <signal name="modified" handler="update_time" object="GcalEditDialog" swapped="no"/>
                   </object>
                   <packing>

src/gcal-edit-dialog.c

@@ -546,25 +546,6 @@ gcal_edit_dialog_constructed (GObject* object)
 
   g_action_map_add_action (G_ACTION_MAP (dialog->action_group), G_ACTION (dialog->action));
 
-  /* bind title & symmary */
-  g_object_bind_property (dialog->summary_entry,
-                          "text",
-                          dialog->titlebar,
-                          "title",
-                          G_BINDING_DEFAULT);
-
-  /* bind all-day check button & time entries */
-  g_object_bind_property (dialog->all_day_check,
-                          "active",
-                          dialog->start_time_selector,
-                          "sensitive",
-                          G_BINDING_DEFAULT | G_BINDING_INVERT_BOOLEAN);
-  g_object_bind_property (dialog->all_day_check,
-                          "active",
-                          dialog->end_time_selector,
-                          "sensitive",
-                          G_BINDING_DEFAULT | G_BINDING_INVERT_BOOLEAN);
-
   /* action area, buttons */
   g_object_set_data (G_OBJECT (dialog->cancel_button),
                      "response",