#2 data item for XferCallback

[David A Knight]

An XferCallback currently provides no way of telling
the source of the callback, namely which jukebox it
came from.

This patch takes the approach of adding a void* data
item to the callback (and all functions which use them)
That way an application can pass an object, for
instance a C++ object or a GObject which wraps up njb
functionality for a single jukebox and so can easily
update the status of the transfer for the correct jukebox.

The patch is against the 0.9.1b release

[David A Knight]

[Linus Walleij]

Logged In: YES
user_id=473872

Fixed ages ago...