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/bugs/code_in_links.md

@@ -0,0 +1,16 @@
+**This bug is now solved**
+
+Previously, a bug would not let you use `code` inside links text.
+
+So this:
+	Use the [`syntax`][syntax]
+produces:
+> Use the [`syntax`][syntax]
+
+And this:
+	Use the `[syntax][syntax]`
+produces:
+> Use the `[syntax][syntax]`
+
+[syntax]: http://gogole.com
+

vendor/plugins/maruku/tests/bugs/complex_escaping.md

@@ -0,0 +1,4 @@
+
+
+What do you see here? `\\` it should be two backslashes.
+