v0.7.15

• Show full ffmpeg command after errors.
• For *_vaapi encoders map --crf to ffmpeg -q (instead of -qp).
• Set av1_vaapi default --max-crf to 255.
• Fix sample-encode printing output to non-terminals.
• Omit "Encode with: ..." stderr hint for non-terminals.
• Support logging enabled when stderr is not a terminal or by setting env var RUST_LOG. E.g:
  • RUST_LOG=ab_av1=info "info" level logs various progress results like sample encode info
  • RUST_LOG=ab_av1=debug "debug" level logs include ffmpeg calls
• Don't panic on non-zero status exit.
• When unable to parse a vmaf score fail faster and include ffmpeg output.
• Add --reference-vfilter arg to sample-encode, crf-search, auto-encode to allow
  overriding --vfilter for VMAF.
• Add --sample-duration arg to configure the duration of each sample. Default 20s.