Flag: markdown no TOC

[steveklabnik]

This issue is part of #125

--markdown-no-toc: don't generate a table of contents

Using this flag looks like this:

$ rustdoc README.md --markdown-no-toc

When generating documentation from a Markdown file, by default, rustdoc will
generate a table of contents. This flag supresses that, and no TOC will be
generated.

---

Should we keep this flag or not?

[steveklabnik]

We don't yet have any support for regular markdown files, and if so, I'm not sure what we'd do with TOCs. Dunno.

[steveklabnik]

We talked about this at the tools team meeting today and the intention is to figure out support for lightly customizing rustdoc's output as a first-class thing, but not necessarily via this low-level mechanism.