pelican-quickstart: switch to jinja2

- Use the jinja2 templating language for Makefile, fabfile,
  pelicanconf, publishconf, and develop-server.sh
- Add logic in pelican_quickstart.py
- Let jinja2 handle opening and reading template files
- Remove thus unused functions for string.Template

pelican/tools/templates/pelicanconf.py.jinja2

@@ -0,0 +1,35 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*- #
+from __future__ import unicode_literals
+
+AUTHOR = {{author}}
+SITENAME = {{sitename}}
+SITEURL = ''
+
+PATH = 'content'
+
+TIMEZONE = {{timezone}}
+
+DEFAULT_LANG = {{lang}}
+
+# Feed generation is usually not desired when developing
+FEED_ALL_ATOM = None
+CATEGORY_FEED_ATOM = None
+TRANSLATION_FEED_ATOM = None
+AUTHOR_FEED_ATOM = None
+AUTHOR_FEED_RSS = None
+
+# Blogroll
+LINKS = (('Pelican', 'http://getpelican.com/'),
+         ('Python.org', 'http://python.org/'),
+         ('Jinja2', 'http://jinja.pocoo.org/'),
+         ('You can modify those links in your config file', '#'),)
+
+# Social widget
+SOCIAL = (('You can add links in your config file', '#'),
+          ('Another social link', '#'),)
+
+DEFAULT_PAGINATION = {{default_pagination}}
+
+# Uncomment following line if you want document-relative URLs when developing
+#RELATIVE_URLS = True