Fix paragraph mark up.
* Require an eol after comments, so that an eol with content after it is
interpreted as a paragraph.
* 'eol >> eol' => 'eol >> *blank_p >> eol_p' so that lines containing
only a comment aren't interpreted as paragraph breaks.
* +eol after 'inside paragraphs' so that all the whitespace following
a paragraph is swallowed up. If it wasn't then it'd create lots of
empty paragraphs when there's a lot of whitespace.
[SVN r62700]
Daniel James