[Azoth Tracolor] Working event colors settings saving.
[Azoth Tracolor] Instantiate & register EventsSettingsManager.
[Azoth Tracolor] Pass EventsSettingsManager to IconsManager.
[Azoth Tracolor] Keep the list of enabled events.
[Azoth Tracolor] Route connections through handleItemChanged().
[Azoth Tracolor] EventsSettingsManager::eventSettingsChanged().
[Azoth Tracolor] IconsManager::clearCaches() slot.
[Azoth Tracolor] Use EventsSettingsManager for events/colors.