This syntax file is for ES7 and future syntax. Need to work with yajs.vim.
Supports:
- Decorator https://github.com/wycats/javascript-decorators
- class property initializer https://gist.github.com/jeffmo/054df782c05639da2adb
- Async/await https://github.com/lukehoban/ecmascript-asyncawait
TODO: