Editing the track list

[sukru cinar <cinarus yahoo com>]

Hello all,

I was making an audio cd with brasero but couldn't find a way to re-order the tracks after I had added them to the project. So I added two buttons
to the brasero-audio-disc dialog to move selected tracks up or down in the
list. 

I could send a diff against 0.8.2 if you think it could be a desirable feature for other users as well.

Regards,
Sukru