Fixes DOC-975, need straight quotes in code blocks

@JAAkana , @mhoeber , @catong , @srpearce 
It seems that the Sphinx template automatically applies the typographically "correct" smart quotes to untagged text but ALSO TO text tagged as an XML code block. It does NOT do so for text tagged as a Python code block or only with the :: formatting identifier. 
However, I have only tested this locally in HTML output. This will need to be merged (or a subset) for us to confirm that the HTML and PDF output actually produced by RTD leaves the quotes alone.  
This PR includes changes to files in the course_authors, shared, and students directories. 
There's no rush on this, but the error was reported back in September.