[1/2] OmniGears: notification drawer: custom clock & calendar shortcut

Base: https://gerrit.omnirom.org/#/c/4811/

PS10:
added AppSelectListPreference and use for clock and calendar

Change-Id: I68b9a8bbb84042cbf4bc448cfc30599132f03256

Conflicts:
	res/values/custom_strings.xml
	res/xml/notification_panel_settings.xml
	src/org/omnirom/omnigears/interfacesettings/NotificationPanelSettings.java