Update vitreum (#946)

- Updates Vitreum to v6.0.1 + some custom fixes.
  - Stylesheets must be imported with `require('./sheet.less');` but can also can now share stylesheets between jsx components.
  - Should eliminate a lot of security concerns with older nested dependencies.
  - Changed a lot of files to make this work
- Also removes dependency on PicoRouter in favor of React-Router

shared/naturalcrit/codeEditor/codeEditor.jsx

@@ -1,3 +1,4 @@
+require('./codeEditor.less');
 const React = require('react');
 const createClass = require('create-react-class');
 const _ = require('lodash');