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/callout.html

@@ -1 +1,10 @@
-<div markdown="span" class="bs-callout bs-callout-{{include.type}}">{{include.content}}</div>
+{% comment %}
+A "callout" (section with colored title and left margin)
+
+Parameters:
+- type: A bootstrap color for the callout (info, warning, danger, default, success,
+  and primary
+- content: markdown content
+{% endcomment -%}
+<div markdown="1" class="bs-callout bs-callout-{{include.type}}">{{include.content}}
+</div>