Remove faye-websocket workaround
Formatter customization via Konacha.config

Fixes #137
Avoid stubbing STDOUT.puts

For some reason this causes problems with Poltergeist 1.3.
Suppress JS errors in Poltergeist

This should be handled by visionmedia/mocha#868, but
PhantomJS probably still has a version of WebKit with
https://bugs.webkit.org/show_bug.cgi?id=67119