Feature request: implement missing features of QtDBus

[black-desk]

1. DBus Standard Interfaces

   DBus spec encourage to use "Standard Interfaces", but QtDBus missing classes or some feature for these interface, make using and have a dbus service implement those interfaces inconvenient.

   • org.freedesktop.DBus.Properties

     QtDBus will not emit the propertiesChanged dbus signal.

• org.freedesktop.DBus.ObjectManager

  This interface is missing. And a feature is missing in QtDBus to make use of this object manager interface.

2. Listen DBus signal from all objects in a subtree.

   DBus spec 0.16 add a new key path_namespace in the rule of "org.freedesktop.DBus.AddMatch" interface.

   https://dbus.freedesktop.org/doc/dbus-specification.html#message-bus-routing-match-rules

   This key can be used in listen signal sent from all the dbus object in a subtree.

   But QDBus does not support this feature.

As an organization make use of DBus heavily, I suggest that we could implement these features in DTKCore.

[kegechen]

DDBusExtendedAbstractInterface 是不是可以满足 propertyChanged 的需求

[black-desk]

DDBusExtendedAbstractInterface 是不是可以满足 propertyChanged 的需求

看起来可以

[asterwyx]

dtkcore里面现在有两个抽象的DBus Interface类（DDBusExtendedAbstractInterface和DDBusInterface），这两个类是不是应该整理一下了。