function XAny(f, xf) {
    this.xf = xf;
    this.f = f;
    this.any = false;
  }
Returns the first argument if it is falsy, otherwise the second argument.
Acts as the boolean `and` statement if both inputs are `Boolean`s.

@func
@memberOf R
@since v0.1.0
@category Logic
@sig a -> b -> a | b
@param {Any} a
@param {Any} b
@return {Any}
@see R.both, R.or
@example

     R.and(true, true); //=> true
     R.and(true, false); //=> false
     R.and(false, true); //=> false
     R.and(false, false); //=> false