Remove Arrow Icon in PullDownContent and ReleaseContent

[yoshimoto8]

Hi, I want to remove arrow icon in PullDownContent and ReleaseContent component. Can I create PR?

I think maybe the correction will be like this

interface PullDownContentProps {
  height?: string
  background?: any
  label?: string
  disabled?: boolean
}

export const ReleaseContent: React.SFC<ReleaseContentProps> = ({
  height = '200px',
  background = 'none',
  label = 'Release to refresh'
  disabled = false
}) => (
  <div id="container">
    {disabled ? null : <div id="arrow"/>}
    <span>{label}</span>
  </div>
)

[echoulen]

looks good