Audio during backward playback

The playback via JKL has improved a lot after the last JB's commit but when you work on spoken text (but this is actually useful when you have to cut music as well) is very useful to have the option to listen the sound when you play backwards (as soon as you listen to something you want to keep, you hit J and you can listen where the point of your interest is without stop and seek.)

I think that the reversed audio playback was removed because of the "rubberband" which keeps the pitch during faster playback. If this is the reason why I suggest to have 2 modalities: with or without pitch correction. When you disable the pitch correction you can listen in both directions