Add Python page

- Update styles for some includes
- Use default markdown rendering instead of span rendering to allow
  multi-line content
- Slight hack in customstyles to allow color overrides. A better fix
  would be to use the bootstrap sass to keep constant colors throughout
  the project
- Added title parameter to note and warning includes

_includes/warning.html

@@ -1 +1,8 @@
-<div markdown="span" class="alert alert-danger" role="alert"><i class="fa fa-exclamation-circle"></i> <b>Warning:</b> {{include.content}}</div>
+{% comment %}
+A red alert box.
+
+Parameters:
+- title: Initial word (default "warning")
+- content: markdown content
+{% endcomment -%}
+<div markdown="1" class="alert alert-danger" role="alert"><i class="fa fa-exclamation-circle"></i> <b>{{include.title | default:"Warning"}}:</b> {{include.content}}</div>