Handles indentation inside pre-formatted Markdown blocks

[davidmerfield]

Pandoc is very strict and treats indents inside HTML blocks as code blocks. This is correct but bad user experience. For instance Pandoc converts this:

<table>
    <td>[Hey!](/goo)</td>
</table>

Into:

<table>
<pre><code><td>[Hey!](/goo)</td></code></pre>
</table>

This is technically correct but not desirable behaviour. We want to mix HTML and Markdown in the same file. So I wrote a function to collapse the indentation for the contents of an HTML tag. More discussion of this issue

---

• Fix a bug in the indent-stripping function so that it will no longer remove the indents for pre formatted text.