[AD] updating objects and retained properties

[Vincent Penquerc'h <Vincent.Penquerch@xxxxxxxxxx>]

Title: updating objects and retained properties

In my alogg lib, I added the ability to select the encoding quality
for the datogg grabber plugin.
However, when updating the datafile, I have no way of knowing the
quality a particular stream was encoded with. I would like to know
this, in order to encode again with the same quality (obviously it
only applies to streams grabbed from WAV/VOC files, not directly
from an Ogg/Vorbis file).
Allegro's grabber already supports this kind of mechanism, though
hardcoded (the grab routine is passed the filename, x/y/w/h, and a
couple other things IIRC). The proper way would probably be to pass
the whole list of properties to the grab function, possibly NULL
if it's not an update but a grab of a new object.
However, it'd break source compatibility.
Comments ?

--
Vincent Penquerc'h