Note that you need a recent version of Node because we use new ES6 features. v7.8.0 is definitely OK - earlier v7 versions are probably fine too.
$ npm install -g gulp-cli
$ (cd runtime && npm install)
$ (cd tracelib && npm install)
$ (cd runtime && gulp)
If there are unhandled promise exceptions without stack traces, use ./node_modules/.bin/mocha --trace-warnings.
$ cd runtime
$ traceFile=`pwd`/trace.json npm test
$ python -m SimpleHTTPServer 5001 &
$ open 'http://localhost:5001/runtime/browser/browser-demo/index.demo.html'