- refactored postal addresses in the Contact record class into

- refactored postal addresses in the Contact record class into
       a new class called PostalAddress
- renamed Address class in record.h to EmailAddress
- moved Contact::GetPostalAddress() to record.cc as part of the
       new PostalAddress class and renamed it
       PostalAddress::GetLabel()
- opensync plugin:
       - refactored vformat helpers into separate base class
	       called vBase
       - added vCard converter class
       - commented out the code that skipped over the adding
	       of empty attribute values and parameters,
	       since VCARD depends on some of this behaviour
       - movified vformat.c:vformat_find_attribute() to take
	       an extra nth argument, in order to search
	       for multiple attributes with the same name...
	       the way this is coded is a bit inefficient...
	       but we're moving away from vformat when we move
	       to OpenSync 0.3x / 0.40, so this is just temporary
	       pain