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/table_attributes.md

@@ -0,0 +1,52 @@
+Write a comment here
+*** Parameters: ***
+{} # params 
+*** Markdown input: ***
+
+h         | h
+----------|--
+{:t}  c1  | c2
+{: summary="Table summary" .class1 style="color:red" border=3 width="50%" frame=lhs rules=cols  cellspacing=2em cellpadding=4px}
+
+{:t: scope="row"}
+*** Output of inspect ***
+md_el(:document,[
+	md_el(:table,[
+		md_el(:head_cell,["h"],{},[]),
+		md_el(:head_cell,["h"],{},[]),
+		md_el(:cell,[" c1"],{},[[:ref, "t"]]),
+		md_el(:cell,["c2"],{},[])
+	],{:align=>[:left, :left]},[["summary", "Table summary"], [:class, "class1"], ["style", "color:red"], ["border", "3"], ["width", "50%"], ["frame", "lhs"], ["rules", "cols"], ["cellspacing", "2em"], ["cellpadding", "4px"]]),
+	md_el(:ald,[],{:ald=>[["scope", "row"]],:ald_id=>"t"},[])
+],{},[])
+*** Output of to_html ***
+<table cellspacing='2em' class='class1' border='3' rules='cols' frame='lhs' summary='Table summary' cellpadding='4px' width='50%' style='color:red'><thead><tr><th>h</th><th>h</th></tr></thead><tbody><tr><th scope='row' style='text-align: left;'> c1</th><td style='text-align: left;'>c2</td>
+</tr></tbody></table>
+*** Output of to_latex ***
+\begin{tabular}{l|l}
+h&h\\
+\hline 
+ c1&c2\\
+\end{tabular}
+*** Output of to_md ***
+hh c1c2
+*** Output of to_s ***
+hh c1c2
+*** EOF ***
+
+
+
+	OK!
+
+
+
+*** Output of Markdown.pl ***
+<p>h         | h
+----------|--
+{:t}  c1  | c2
+{: summary="Table summary" .class1 style="color:red" border=3 width="50%" frame=lhs rules=cols  cellspacing=2em cellpadding=4px}</p>
+
+<p>{:t: scope="row"}</p>
+
+*** Output of Markdown.pl (parsed) ***
+Error: #<NoMethodError: private method `write_children' called for <div> ... </>:REXML::Element>