old_contents: /* eslint-env node */
  module.exports = {
    browsers: [
      'ie 9',
      'last 1 Chrome versions',
      'last 1 Firefox versions',
      'last 1 Safari versions'
    ]
  };
  
new_contents: /* eslint-env node */
  module.exports = {
    browsers: [
      "> 1%",
      "last 2 versions"
    ]
  };
  
subject: include IE11 as supported browser. Closes #12