Update to latest HTML5lib, Add Maruku testdir

Sync with the latest html5lib.
Having the Maruku unit tests on-hand may be useful for debugging; so let's include them.

vendor/plugins/maruku/tests/unittest/data_loss.md

@@ -0,0 +1,42 @@
+Write a comment here
+*** Parameters: ***
+{} # params 
+*** Markdown input: ***
+1. abcd
+efgh
+ijkl
+
+*** Output of inspect ***
+md_el(:document,[
+	md_el(:ol,[md_el(:li_span,["abcd efgh ijkl"],{:want_my_paragraph=>false},[])],{},[])
+],{},[])
+*** Output of to_html ***
+<ol>
+<li>abcd efgh ijkl</li>
+</ol>
+*** Output of to_latex ***
+\begin{enumerate}%
+\item abcd efgh ijkl
+
+\end{enumerate}
+*** Output of to_md ***
+1.  abcd efgh ijkl
+*** Output of to_s ***
+abcd efgh ijkl
+*** EOF ***
+
+
+
+	OK!
+
+
+
+*** Output of Markdown.pl ***
+<ol>
+<li>abcd
+efgh
+ijkl</li>
+</ol>
+
+*** Output of Markdown.pl (parsed) ***
+Error: #<NoMethodError: private method `write_children' called for <div> ... </>:REXML::Element>