message: export OcticonButton from src/index.js
diff: @@ -12,6 +12,7 @@ export {default as ButtonDanger} from './ButtonDanger'
  export {default as ButtonPrimary} from './ButtonPrimary'
  export {default as ButtonOutline} from './ButtonOutline'
  export {default as ButtonLink} from './ButtonLink'
  +export {default as OcticonButton} from './OcticonButton'
  export {default as Caret} from './Caret'
  export {default as CaretBox} from './CaretBox'
  