switch from travis to circleci

Author: pd0wm

.travis.yml

@@ -13,7 +13,7 @@ It uses an [STM32F413](http://www.st.com/en/microcontrollers/stm32f413-423.html?
 
 It is 2nd gen hardware, reusing code and parts from the [NEO](https://github.com/commaai/neo) interface board.
 
-[![Build Status](https://travis-ci.org/commaai/panda.svg?branch=master)](https://travis-ci.org/commaai/panda)
+[![CircleCI](https://circleci.com/gh/commaai/panda.svg?style=svg)](https://circleci.com/gh/commaai/panda)
 
 Usage
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