Indent paragraphs, allowing the indentation to collapse if already indented within a parent.  Also remove how renderer could define leading space, instead requiring the node to insert spaces directly.
Indent paragraphs, allowing the indentation to collapse if already indented
within a parent.  Also remove how renderer could define leading space,
instead requiring the node to insert spaces directly.

kristapsdz/lowdown,kristapsdz/lowdown,kristapsdz/lowdown