message: refactor Avatar a bit
  move query parameter handling to getImageURL() and export that
  rename "child" prop to "isChild" for clarity
diff: @@ -3,35 +3,45 @@ import classnames from 'classnames'
  const IMAGE_BASE_URL = 'https://avatars.githubusercontent.com/'
  +function getImageURL(username, params) {
  + const query = params ? `?${new URLSearchParams(params)}` : ''
  + return `${IMAGE_BASE_URL}${username}${query}`
  +}
  +
  const Avatar = props => {
  const {
  - username,
  + username = 'github',
  size = 20,
  - baseURL = IMAGE_BASE_URL,
  - alt,
  - child,
  + isChild,
  ...rest
  } = props
  - const query = new URLSearchParams({
  +
  + const params = {
  v: 3, // XXX is this necessary?
  s: size * 2
  - })
  + }
  +
  + const {
  + alt = username,
  + src = getImageURL(username, params)
  + } = rest
  +
  return (
  <img
  className={classnames(
  'avatar',
  {
  'avatar-small': size <= 24,
  - 'avatar-child': child,
  + 'avatar-child': isChild,
  }
  )}
  - src={`${baseURL}${username || 'github'}?${query}`}
  + src={src}
  + alt={alt}
  width={size}
  height={size}
  - alt={alt || username}
  />
  )
  }
  export default Avatar
  -export {IMAGE_BASE_URL}
  +export {IMAGE_BASE_URL, getImageURL}
  