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/inline_html2.md

@@ -0,0 +1,36 @@
+
+*** Parameters: ***
+{}
+*** Markdown input: ***
+<div markdown="1">Test **bold**</div>
+<p markdown="1">Test **bold**</p>
+*** Output of inspect ***
+md_el(:document,[
+	md_html("<div markdown=\"1\">Test **bold**</div>"),
+	md_html("<p markdown=\"1\">Test **bold**</p>")
+],{},[])
+*** Output of to_html ***
+<div>
+<p>Test <strong>bold</strong></p>
+</div><p>Test <strong>bold</strong></p>
+*** Output of to_latex ***
+
+*** Output of to_md ***
+
+*** Output of to_s ***
+
+*** EOF ***
+
+
+
+	OK!
+
+
+
+*** Output of Markdown.pl ***
+<div markdown="1">Test **bold**</div>
+
+<p markdown="1">Test **bold**</p>
+
+*** Output of Markdown.pl (parsed) ***
+Error: #<NoMethodError: private method `write_children' called for <div> ... </>:REXML::Element>