code: function Property( field, value, params ) {
  
    if( !(this instanceof Property) )
      return new Property( value )
  
    if( params != null )
      Object.assign( this, params )
  
    this._field = field
    this._data = value
  
    Object.defineProperty( this, '_field', { enumerable: false })
    Object.defineProperty( this, '_data', { enumerable: false })
  
  }
docs: vCard Property
  @constructor
  @memberOf vCard
  @param {String} field
  @param {String} value
  @param {Object} params
  @return {Property}