In other words, the message callbacks are now shared across all LibVLC
instances. That is a requirement to enable:
 - LibVLC applications to catch messages during LibVLC init/deinit,
 - emitting log messages when no VLC object point is available.

That makes no difference for VLC interfaces, since there is only one
LibVLC instances in a VLC process.

macosx: work-around CoreAnimation limitations on 10.6, which prevented the correct display of some ui elements

macosx: show the playlist size as a badge in the sidebar and fixed an appearance issue of the sidebar

macosx: converted interface builder files from nib to the more modern xib file format, which smaller and more suitable for git

Modified-by and Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

There is no potentially cancellation-unsafe code here (unlike Qt4),
since msg_Free() is safe and vlc_mutex_*() of course too.

Contrary to C, C++ compilers don't promote larger constants up to
unsigned long long when needed.

No need to invoke vlc-config to expand a shell variable.