Return avatar which provides one of the given interfaces.
|Parameters||avatarId||a string that identifies an avatar, as returned by |
(via a Deferred). Alternatively, it may be
|mind||usually None. See the description of mind in |
|interfaces||the interface(s) the returned avatar should implement, e.g.
IMailAccount. See the description of
|Returns||a deferred which will fire a tuple of (interface, avatarAspect, logout),
or the tuple itself. The interface will be one of the interfaces passed in
the 'interfaces' argument. The 'avatarAspect' will implement that
interface. The 'logout' object is a callable which will detach the mind
from the avatar.