add missing python dependencies

requirements.txt

@@ -3,3 +3,22 @@ pelican-i18n-subsites
 pelican-render-math
 pelican-tag-cloud
 beautifulsoup4
+Markdown
+
+appdirs
+blinker
+docutils
+feedgenerator
+Jinja2
+lxml
+Markdown
+MarkupSafe
+packaging
+Pygments
+pyparsing
+python-dateutil
+pytz
+six
+smartypants
+typogrify
+Unidecode