overlay_update
=============================================================================
Class for maintaining overlays in MP aircraft. It is used in Nasal code that's
embedded in aircraft animation XML files, and checks in intervals whether the
parent aircraft has changed an overlay, in which case it copies the respective
overlay to the aircraft's root directory.
SYNOPSIS:
livery_update.new();
livery_update.add(<overlay-dir>, <property> [, <callback>]);
<overlay-dir> ... directory with overlay files, relative to $FG_ROOT
<property> ... MP property where the overlay file name can be found
(usually one of the sim/multiplay/generic/string properties)
<callback> ... callback function that's called with two arguments:
the file name (without extension) and the overlay directory
EXAMPLE:
<nasal>
<load>
var update = aircraft.overlay_update.new();
update.add("Aircraft/F4U/Models/Logos", "sim/multiplay/generic/string");
</load>
<unload>
update.stop();
</unload>
</nasal>