Shortcodes for YouTube and iframes

Added shortcodes 2.5.0 as dependency; Earlier versions corrupted
non-ASCII characters, see
https://github.com/dmulholland/shortcodes/issues/6

The rendered elements have a `shortcode` CSS class.

The YouTube shortcode supports various ways to refer to a video:

    - `{youtube VideoID}`
    - `{youtube youtube.com or youtu.be URL}`

URLs containing an '=' should be quoted, or otherwise the shortcodes
library will parse it as "key=value" pair.

The IFrame shortcode supports the `cap` and `nocap` attributes. `cap`
indicates the required capability the user should have in order to
render the tag. If `nocap` is given, its contents are shown as a message
to users who do not have this tag; without it, the iframe is silently
hidden.

`{iframe src='https://source' cap='subscriber' nocap='Subscribe to view'}`

Merged test code + added HTML class for shortcode iframes

tests/test_web/test_jinja.py

@@ -23,9 +23,21 @@ class MarkdownTest(unittest.TestCase):
     def test_markdowned(self):
         from pillar.web import jinja
 
-        self.assertEqual(None, jinja.do_markdowned({'eek': None}, 'eek'))
+        self.assertEqual('', jinja.do_markdowned({'eek': None}, 'eek'))
         self.assertEqual('<p>ook</p>\n', jinja.do_markdowned({'eek': 'ook'}, 'eek'))
         self.assertEqual('<p>ook</p>\n', jinja.do_markdowned(
             {'eek': 'ook', '_eek_html': None}, 'eek'))
         self.assertEqual('prerendered', jinja.do_markdowned(
             {'eek': 'ook', '_eek_html': 'prerendered'}, 'eek'))
+
+    def test_markdowned_with_shortcodes(self):
+        from pillar.web import jinja
+
+        self.assertEqual(
+            '<dl><dt>test</dt><dt>a</dt><dd>b</dd><dt>c</dt><dd>d</dd></dl>\n',
+            jinja.do_markdowned({'eek': '{test a="b" c="d"}'}, 'eek'))
+
+        self.assertEqual(
+            '<h1>Title</h1>\n<p>Before</p>\n'
+            '<dl><dt>test</dt><dt>a</dt><dd>b</dd><dt>c</dt><dd>d</dd></dl>\n',
+            jinja.do_markdowned({'eek': '# Title\n\nBefore\n{test a="b" c="d"}'}, 'eek'))