For lists, use tab instead of space for indent.

This has no effect on rendered HTML.
However, it is a change that will allow for improved and correct
support of multiple nested lists with rich content inside.
In the end, this is a formatting change that "makes the most sense"
when considering all of Markdown features and how they interact.
It also more closely matches the original nested lists examples in
Markdown description (see
http://daringfireball.net/projects/markdown/syntax#list).
Add failing test case for nested lists.
Update README.md.

Do not include $ in installation steps.
Use new WIP list item formatting.
More general solution for indenting list items, with better nested support.

Also better support for large spacing (via paragraphs) between list
items.
The implementation is still quite messy because the rules for Markdown
lists and the parser output is quite messy.
Update Godeps.
Merge pull request #14 from shurcooL/improve-nested-list-support

Improve nested list support.