Returns service features list.
The Features Property syntax has these parts:
||An expression evaluating to an object
of type XMPPService.
Provides you with features that are supported for the
specific service. This property provides you with reference
to collection of XMPPFeature objects, each of them
describing certain feature service supports. One service
can support several features. For example, MSN gateway
service supports regular Chat, but also GroupChat, provides
VCard details about each user etc..