docs(README.md): use our badges and mention this is a fork

Author: cwillisf

README.md

@@ -1,4 +1,10 @@
-# Paper.js - The Swiss Army Knife of Vector Graphics Scripting [![Build Status](https://travis-ci.org/paperjs/paper.js.svg?branch=develop)](https://travis-ci.org/paperjs/paper.js) [![NPM](https://img.shields.io/npm/v/paper.svg)](https://www.npmjs.com/package/paper)
+# Scratch's fork of Paper.js [![Build Status](https://circleci.com/gh/LLK/paper.js.svg?style=shield)](https://app.circleci.com/pipelines/github/LLK/paper.js?branch=develop) [![NPM](https://img.shields.io/npm/v/@scratch/paper.svg)](https://www.npmjs.com/package/@scratch/paper)
+
+This is a fork of Paper.js for use in Scratch. Please do not contact the Paper.js authors to support this fork.
+
+_Original README.md below_
+
+# Paper.js - The Swiss Army Knife of Vector Graphics Scripting
 
 If you want to work with Paper.js, simply download the latest "stable" version
 from [http://paperjs.org/download/](http://paperjs.org/download/)