Export range of frames

[slowtiger]

The request to restore v10 behaviour in the export panel seems a good opportunity to improve that whole thing. I like to suggest this:

1. Like now, type in start and end frames - but Mark Out should allow to be higher than last content frame in timeline. (This is to make use of "repeat frames" without having to create and expand some other layer.)
2. A button for "Use selected frames".
3. A button for "Use In/Out Marker".

And while we're at it:
4. Selecting RGBA should automatically disable Background by default - with ability to switch that on by hand. (This is one of my regulary fuck-ups: rendering a scene with Alpha, but forgot to switch of BG.)

[melanie]

Thank you for your feedback. Added to our To-Do List.