This is purely distributed under GPL v2 license and distributed as is without any warranty, as usual.
The main and only feature is that the bookmarklet is smart enough to deal correctly with not only single videos, but with ones that are part of playlists. Mainly disability of any other addons/extensions out there to deal with playlists forced me to write my own solution.
- Download the youtube_bm.html file an open it up in your browser.
- Drag the link provided there to your browser's bookmark bar.
- When watching any video (including ones in playlist) on youtube website, click on newly placed bookmark.