Avoid using Bootstrap class names in HTML

[trevormunoz]

E.g., https://github.com/umd-mith/sga/blob/master/site/_pages/linear_tocs/prometheus_unbound.html#L7

I'd like to see us trying using Bootstrap's sass files to keep class names in our HTML as semantic as possible. This would me adding a little more to our build process to transform sass => css