Code highlighting

[bhague1281]

Currently, code blocks are displaying without any syntax highlighting, and many blocks have improperly placed language tags and formatting, such as this page:

http://localhost:4000/api-reference/authentication/apidoc.html

Add code highlighting and fix code block formatting. Possible stylesheets: https://github.com/richleland/pygments-css

[bhague1281]

#826
#828