* php/HAB/Pica/Record/Record.php ($_parent): New variable. Containing
parent record.

* php/HAB/Pica/Record/LocalRecord.php (containsCopyRecord): New
function. Return true if local record contains a copy record.
* php/HAB/Pica/Record/TitleRecord.php (containsLocalRecord): New
function. Return true if title record contains a local record.

* php/HAB/Pica/Record/NestedRecord.php (containsRecord): New
function. Return true if nested records contains a record.
(addRecord): Use new function.

* NestedRecord.php (getFields): Do not delegate getFields() to
contained records when called with selector.

Record::select() calls getFields() w/o arguments which returns all
fields.

Returns the first of all fields that are matched by a field selector.

of fields identified by a tag