A few UI issues

[YaakovDavis]

1. Code segments don't show commas, dots, colons, and parentheses (a screenshot is attached).
2. In multi-video units, the website doesn't remember which ones I watched.
3. When switching to another video while a video is playing, playback doesn't stop.

[rasbt]

Sorry, missed this last week somehow! Thanks a lot for the note, I will discuss this with out web dev, and hopefully we can address all of these asap.

[rasbt]

Happy to report that the

When switching to another video while a video is playing, playback doesn't stop.

issue is fixed now!