Issue #136: Syntax highlighting support (conservancy/kallithea)

[Sam Jaques]

New issue 136: Syntax highlighting support
https://bitbucket.org/conservancy/kallithea/issue/136/syntax-highlighting-support

Sam Jaques:

It seems CodeMirror supports this already.
This is used for the side-by-side diff, don't know if it's used in the default view.

E.g.:
```
#!javascript

var editor = CodeMirror.fromTextArea('code1', {
  height: "150px",
  parserfile: "codemirror/contrib/sql/js/parsesql.js",
  path: "codemirror/js/",
  stylesheet: "css/sqlcolors.css",
  textWrapping: true
});
```