Create a better designed error handler page

[matthewp]

Currently errors are forwarded to the client as text. Since this is a development tool we should do a better job of designing these.

[matthewp]

Here's the plan on the design:

1. We will handle errors directly instead of letting it go through express (which just forwards them to the client as text).
2. The error will be passed to https://github.com/donejs/donejs-error-format which will extract the relevant parts of the error message.
3. errorFormat.html(parts) -> HTML will give us back the HTML.
4. We will clear the console (create-react-app does the same, giving the error message more focus).
5. errorFormat.console(parts) -> Text will give us formatted Text that can be logged to the console.

[matthewp]

Usage like this:

const errorFormat = require("donejs-error-format");

app.use(function(err, req, res, next){
  let parts = errorFormat.extract(err);
  let html = errorFormat.html(parts);

  // TODO format the console version, clear, and log

  res.type('html').end(html);
});

[matthewp]

https://github.com/donejs/donejs-error-format

[matthewp]

This was done in #102