Add md extensions, Fix page list generation

Source/Libs/markdown/extensions/mdx_subscript.py

@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+"""Markdown Subscript Extension
+
+Extends the Python-Markdown library to support subscript text.
+
+Given the text:
+    The molecular composition of water is H~2~O.
+Will output:
+    <p>The molecular composition of water is H<sub>2</sub>O.</p>
+
+:website: https://github.com/jambonrose/markdown_subscript_extension
+:copyright: Copyright 2014-2018 Andrew Pinkham
+:license: Simplified BSD, see LICENSE for details.
+"""
+
+from __future__ import unicode_literals
+
+from . import Extension
+from ..inlinepatterns import SimpleTagPattern
+
+# match ~, at least one character that is not ~, and ~ again
+SUBSCRIPT_RE = r"(\~)([^\~]+)\2"
+
+
+def makeExtension(*args, **kwargs):  # noqa: N802
+    """Inform Markdown of the existence of the extension."""
+    return SubscriptExtension(*args, **kwargs)
+
+
+class SubscriptExtension(Extension):
+    """Extension: text between ~ characters will be subscripted."""
+
+    def extendMarkdown(self, md, md_globals):  # noqa: N802
+        """Insert 'subscript' pattern before 'not_strong' pattern."""
+        md.inlinePatterns.add(
+            "subscript", SimpleTagPattern(SUBSCRIPT_RE, "sub"), "<not_strong"
+        )