Wishlist: Active Playback Frame rate stat

[epiil]

It would be great to have an active frame rate stat in the playback filter window to observe any differences between a file's intrinsic frame rate and the frame rate during playback.

[epiil]

This might be redundant with @kieranjol's request in #81, so feel free to close if that's the case.

[kieranjol]

I don't think my request is the same as yours. I wanted to see at what speed QCTools could actually generate the graphs.

[epiil]

@kieranjol ah, thanks for clarfiying