Add a way to bypass the options[:tags] whitelist

[tuzz]

Readability is primarily concerned with extracting text, not images. We are using readability to extract images by setting tags: %w[img] which preserves tags in the output HTML. However, this won’t work if the image is nested under a non-whitelisted node, e.g.

<figure>
  <img src=“…” />
</figure>

I think we basically just want to whitelist all nodes for extraction because our code already handles stripping out nodes it doesn’t care about. Therefore, add a mechanism to bypass the node whitelisting by setting tags: %w[*], i.e. a wildcard.

[cantino]

Thanks!