Document weird implementation of avsc

[elliotsayes]

From package.json:
"avsc": "https://github.com/Bundlr-Network/avsc#csp-fixes"

Would be nice to have the reason for this properly documented or and/or the package uploaded to npm.

[JesseTheRobot]

This version of AVSC is modified to not use internal unsafe eval statements (or code that results in eval calls), to allow for bundlr to be used in sites with CSP (hence the branch name)

[elliotsayes]

I see, just saw the PR here which explains it in more detail: mtth/avsc#223