- Arrays can now be externalized and internalized in the same way
dictionaries can.
- Add new "externalize to file" and "internalize from file" functions
to make reading a property list from a file and writing a property
list to a file more convenient.
- Many assertions in the object implementations are gone. Instead,
calling an accessor for one object type with a different object type
as an argument will return a suitable "invalid" value.
- prop_object_type() now returns a new PROP_TYPE_UNKNOWN value if called
with a NULL object.
- Externalized property lists now contain a reference to the Apple XML
plist DTD.
- Add a new prop_ingest(3) facility, which provides a convenient way to
translate a dictionary into an arbitrary binary representation.