Whitespace at the beginning of a paragraph is stripped away.

   Whitespace within a paragraph is normalized like this: Control
characters (this includes newline) are converted to spaces.  Multiple
spaces are collapsed into a single space character.  Two spaces are
kept after a dot.  A dot, followed by a newline, is converted to
"dot<SPACE><SPACE>".

   Whitespace at the end of a paragraph is stripped.

