Support for vCard contacts

KContact provides an API for contacts/address book data following the vCard standard (RFC 2425 / RFC 2426).

• vCard data model (see KContacts::Addressee).
• vCard input/output (see KContacts::VCardConverter).
• Contact group management (see KContacts::ContactGroup).
• Locale-aware address formatting (see KContacts::Address).
• Address formatting metadata for 190+ countries (see KContacts::AddressFormat).