[addLogo] Active Filters fade in/out

[Jan Gruuthuse]

5ede40c            [addLogo] Add fade-in / fade-out feature for logo image + fix timing initially not displayed in the filter configuration preview + fix logo image missing in the preview in the filter manager.

Looks like this still needs some tweaking. Once filter is applied. And you open filter again: the Fade in/out duration is not there to edit.

It does work when video is rendered.
youtube small sample: Add Logo filter has now a fade lead in/out time

[eumagga0x2a]

Thank you for promptly reporting the issue, should be fixed by [addLogo] Fix dialog constructor, round fade-in duration to the nearest 100 ms, remove unused leftover variable.

[Jan Gruuthuse]

Great, tweaked and improved, thanks.