Use a singleton `Jid` inside the connection instead of always re-creating
a `Jid` from the same string.
Signed-off-by: Steffen Jaeckel <jaeckel-floss@eyet-services.de>
Only nicknames, photos, birthdays, addresses, telephone numbers, emails,
JIDs, titles, roles, notes, and URLs are supported
Due to the synopsis array not having enough space, `/vcard photo
open-self` and `/vcard photo save-self` are not documented properly in
the synopsis section of the `/vcard` command, but they are documented in
the arguments section
Fixed memory leak in vcard autocomplete (thanks to debXwoody)
