message: Update README.md
  Add MIT license badge
diff: -# meshoptimizer [![Build Status](https://travis-ci.org/zeux/meshoptimizer.svg?branch=master)](https://travis-ci.org/zeux/meshoptimizer) [![Build status](https://ci.appveyor.com/api/projects/status/ptx6p8wmqchivawq?svg=true)](https://ci.appveyor.com/project/zeux/meshoptimizer) [![codecov.io](http://codecov.io/github/zeux/meshoptimizer/coverage.svg?branch=master)](http://codecov.io/github/zeux/meshoptimizer?branch=master)
  +# meshoptimizer [![Build Status](https://travis-ci.org/zeux/meshoptimizer.svg?branch=master)](https://travis-ci.org/zeux/meshoptimizer) [![Build status](https://ci.appveyor.com/api/projects/status/ptx6p8wmqchivawq?svg=true)](https://ci.appveyor.com/project/zeux/meshoptimizer) [![codecov.io](http://codecov.io/github/zeux/meshoptimizer/coverage.svg?branch=master)](http://codecov.io/github/zeux/meshoptimizer?branch=master) ![MIT](https://img.shields.io/badge/license-MIT-blue.svg)
  ## Purpose
  