Function globals io read_properties

Load XML file in FlightGear's native <PropertyList> format.
If the second, optional target parameter is set, then the properties
are loaded to this node in the global property tree. Otherwise they
are returned as a separate props.Node tree. Returns the data as a
props.Node on success or nil on error.

Usage:   io.read_properties(<filename> [, <props.Node or property-path>]);

Examples:

var target = props.globals.getNode("/sim/model");
io.read_properties("/tmp/foo.xml", target);

var data = io.read_properties("/tmp/foo.xml", "/sim/model");
var data = io.read_properties("/tmp/foo.xml");