* libversit/vobject.c: Fix handling of QUOTED-PRINTABLE strings.
writeQPString has been fixed to escape all chars according to rfc 1521.
writeString has been added for writing regular non-quoted strings.

* gmomecard/card.c: Fix infinite file growth problems, by not adding
the same attribute to the vcard property more than once.

* gnomecard/address-conduit.[ch]: Remove custom \n escaping and always
use QUOTED-PRINTABLE when necessary because libversit has been
fixed appropriately. Also remove various compiler warnings.

svn path=/trunk/; revision=1527