The Tor Browser bundle clears cookies on exit. There are some plugins you can add to clear them on tab close too. As for something like CDN cookies, I'm actually not sure. But if you have cookies that are set by the CDN for their domain, then it's not trivial to link the loading page (assuming Referrer headers are stripped) to the resource being loaded because TBB uses different Tor circuits for different websites.
I think running any addons or plugins within Tor Browser is a bad idea. Even if it's from a "respected" source, the risk of it somehow becoming compromised is not worth it. IIRC the bundle even advises you that addons may be risky. Considering that the purpose of Tor is to remain anonymous, one should keep in mind that any addon could de-anonymize you.
> IIRC the bundle even advises you that addons may be risky.
The reason for this is that by installing various non-default addons, you're actually making your browser more unique. As a consequence, you're making it easier to link all of your Tor activity back to a single person.
