Get HtmlReader to work again

wrote unit tests and documentation, improved regular expression.
The HtmlReader is enabled by default now and parses metadata in html
files of the form:
<!-- key:value -->

tests/test_readers.py

@@ -90,3 +90,24 @@ class MdReaderTest(unittest.TestCase):
                 "<p>This is another markdown test file.  Uses the mkd extension.</p>"
         
         self.assertEqual(content, expected)
+
+
+class HtmlReaderTest(unittest.TestCase):
+
+    def test_article_with_metadata(self):
+        reader = readers.HtmlReader({})
+        content, metadata = reader.read(_filename('article_with_html_metadata.html'))
+        expected = {
+            'category': 'yeah',
+            'author': u'Alexis Métaireau',
+            'title': 'A great html article with metadata',
+            'summary': u'Multi-line metadata should be'\
+                       u' supported\nas well as <strong>inline'\
+                       u' markup</strong>.',
+            'date': datetime.datetime(2010, 12, 2, 10, 14),
+            'tags': ['foo', 'bar', 'foobar'],
+            'custom_field': 'http://notmyidea.org',
+        }
+
+        for key, value in expected.items():
+            self.assertEquals(value, metadata[key], key)