message: Added transparent props to header.
  Support for issue (Header absolute/fixed value with transparent background)
diff: @@ -39,6 +39,15 @@ export default (variables = variable) => {
  }
  }
  },
  + ".transparent": {
  + backgroundColor: "transparent",
  + borderBottomColor: "transparent",
  + elevation: 0,
  + shadowColor: null,
  + shadowOffset: null,
  + shadowRadius: null,
  + shadowOpacity: null
  + },
  ".noShadow": {
  elevation: 0,
  shadowColor: null,
  