Merge branch 'blender-v2.92-release'

Merge branch 'blender-v2.92-release'

Fix T83267: Crash prefetching scene strip in meta strip

Scene strips can't be prefetched and seq_prefetch_do_skip_frame()
should check if scene strip is in timeline. But it did not recurse into
meta strips, which resulted in crash.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D9999

Fix T82698: Speed effect not working on generator strips

Generator strips with zero inputs have their length set to 1 pernamently.

In some cases it is useful to use speed effect on these strips because they
can be animated. This can be done by using their length as is on timeline as
content length.

This is very simplified and temporary solution, as cutting these strips won't
give expected results. Lot of code relies on length of these strips being fixed
to 1, resolving this properly should be done by T59540.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D10026

Fix T83266: Proxy building with meta strips fails

Building proxy with meta strip selected resulted in attempt to render
meta strip itself and save result as image as is done when building
image proxies.

Remove meta strip from list of supported strips.

Multicam, Meta and scene strip are cleared from poll function in UI as well.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D10001

VSE: Remove skip_disk_cache argument

This argument was used to prevent infinite loop in lookups between disk
and RAM cache.

Code was refactored, so this can be handled internally in cache.

Reviewed By: sybren, sergey

Differential Revision: https://developer.blender.org/D9955

VSE: store raw images in cache

Previously raw images were not cached if image wasn't preprocessed.
This caused issue, that image had to be read from disk on every redraw.

Effect strips must be excluded, because this would cause problem with
invalidation. Effect strips can use preprocessing however. This is
mainly to allow usimg modifiers on them.

This change should follow rBf448ff2afe7a77, but I have wrongly assumed,
that it has been implemented already.

ref T80278

Fix versioning code outside of version check

Bug introduced in f448ff2afe7a probably due to mistake when resolving
conflicts and not checking functionality.

Fix sequencer disk cache not writing data

Error handling added in 512a23c3d61d caused that reading header of new
file failed, since it is empty.

Don't attempt to read header if file is empty. If header can not be read
anyway, try to delete the file. Add asserts, as this should never
happen.

Reviewed By: sybren

Differential Revision: https://developer.blender.org/D9954

VSE: Remove fit method tool setting from header

This property was intended to affect fit method for added strips prior
to running operator. However UI team did not agree with current
implementation.

ref T84535

Reviewed By: HooglyBoogly

Differential Revision: https://developer.blender.org/D10055