Customization of markdown renderer and editor

[Uzay-G]

Linked to #203 (comment).

Would be nice for users to be able to customize the markdown plugins / renderer used and with which options.

Ideas on how we could structure this would be really useful because I'm not sure what the best design would be.

[edditler]

It would probably be best to include more sections in config.yml next to the search configuration and allow users to change those settings from within the app. The simplest settings are these:

var md = require('markdown-it')({
  html:         true/false,        // Enable HTML tags in source
  xhtmlOut:     true/false,        // Use '/' to close single tags (<br />).
  breaks:       true/false,        // Convert '\n' in paragraphs into <br>
  linkify:      true/false,        // Autoconvert URL-like text to links
  typographer:  true/false,
  highlight:    function (/*str, lang*/) { return ''; }

What makes it a bit messy is that this config has to be passed to each template or put into a global variable like session.config.

[BrianGilbert]

#195 related

[Uzay-G]

This is fixed in #241 !