Support viewing Markdown in browser

[Anton Ekblad]

Students often upload reports in Markdown (.md) format. Being able to view these in the web UI would be quite useful.

This could be accomplished either by converting any .md files into HTML (similar to what happens with source code), or by simply serving up the .md file with MIME type text/markdown.

[Evgeny Kotelnikov]

Sounds reasonable! I'll look into both of your suggestions.