[Telepathy] ContactInfo interface deprecated

[Robert McQueen]

I've just marked the ContactInfo interface as deprecated in 0.12 and
0.13 because it really sucks. It requires the client to do parsing of
this horrible XML vCard format from the stone-age, which is only used by
Jabber's vcard-temp semi-deprecated JEP. Gabble already had this code
commented out due to the suckiness of exposing this to the client.

In 0.13 I would like to make the ContactInfo interface do something more
clever with perhaps a dictionary of key/value pairs, or an array of
structures with different fields in (depending if we need to store eg
enum values saying HOME/WORK/DEFAULT/etc). Then other protocols could
easily parse their info format into this, as could Gabble for the vCard
XML. This would also make it easier for us to optionally support the
alternative Jabber contact info mechanism, based on PubSub and not using
the vCard XML format.

Regards,
Rob