Support black listing some sites

[autarch]

It'd be really nice to be able to disable this extension on selected sites. For example, when trying to work with Google Sheets the Edit with Emacs button that appears for every cell is incredibly annoying.

If I find the tuits, I'll try come up with a patch for this.

[stsquad]

This would be a useful feature. I would suggest it's something you could trigger from the toolbar menu much like the Ad blocker whitelisting functions.