ref(ci): remove travis; update badge

Author: Vaughn Dice

.travis.yml

@@ -1,6 +1,6 @@
 # Deis Slugbuilder v2
 
-[![Build Status](https://travis-ci.org/deis/slugbuilder.svg?branch=master)](https://travis-ci.org/deis/slugbuilder)
+[![Build Status](https://ci.deis.io/job/slugbuilder/badge/icon)](https://ci.deis.io/job/slugbuilder)
 [![Docker Repository on Quay](https://quay.io/repository/deisci/slugbuilder/status "Docker Repository on Quay")](https://quay.io/repository/deisci/slugbuilder)
 
 Deis (pronounced DAY-iss) Workflow is an open source Platform as a Service (PaaS) that adds a developer-friendly layer to any [Kubernetes](http://kubernetes.io) cluster, making it easy to deploy and manage applications on your own servers.