Add 1.x migration info to README
Add a clone() method
Add method categories to JSDoc navigation
Enhance callback documentation and make JSDoc TOC floating
Enhance error handling, passing ffmpeg error messages to 'error' handler
JSDoc: enable pretty-printing examples in index page
Fix input stream readable check
New filters syntax and filtergraphs
Add multiple output support, remove migration info

Migration guide was moved to the project wiki.
Enable selecting input when running ffprobe
Rewrite takeScreenshots and mergeToFile