Adds helper method createItemsFromExternalPasteboard: returning
an array of file items from the pasteboard.
performDragOperation: in VLCCoreInteraction is the now only place
where we try to add the dropped file as a subtitle.

Logs are not recorded in background, so do not retain old logs
to avoid confusion.

Those rtf files were awful to read, and rather unhandy. Switch to
plain txt which should make debugging more easy.

Manipulate the data source on the main thread to fix some unprotected
accesses to the array.

Increase the maximum number of lines, for a more complete log.

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

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

Due to hls we we waiting for demuxer to start, which would
load the demuxer source (sub playlist then) and from that
file we would have the format and change the demux if
required.

The problem is that any unsupported format (like split subtitles)
is now being to be demuxed and gets probed and demuxed.

Otherwise can make use of malloc(0) buffers