Add vCard support

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)

src/event/common.c

@@ -41,6 +41,7 @@
 #include "xmpp/roster_list.h"
 #include "xmpp/muc.h"
 #include "xmpp/xmpp.h"
+#include "xmpp/vcard_funcs.h"
 #include "database.h"
 #include "tools/bookmark_ignore.h"
 
@@ -73,6 +74,7 @@ ev_disconnect_cleanup(void)
 #endif
     log_database_close();
     bookmark_ignore_on_disconnect();
+    vcard_user_free();
 }
 
 gboolean