ffmpeg_converter 6.x-1.0-beta2

Another beta release with mostly bug fixes.

#442166 by sndev: Fixing destination token error.

Followup for #528974: changing README to account for the ability to add presets.

#528974 by venkatd: Ability to add new encoding presets.

#631012 by zoo33: Conversion fails with chained custom commands

#403456 by Jax & zoo33: Output size and padding calculation broken.

#428056 by whoastdev: CCK field validation is screwy.

#439500 by whoastdev: Don't display message for files that don't need to be converted.

Clear the cached list of queued files regardless of whether the conversion was successful or not.

Updating doxygen comment to reflect earlier API changes.

#401964: Field display setting is not respected when displaying node through a view.