code: function roundn( x, n ) {
  	var scalar = pow( 10, -n );
  	return round( x*scalar ) / scalar;
  }
docs: ROUNDN // 
  FUNCTION: roundn( x, n )
  Rounds a numeric value to the nearest multiple of 10^n.
  
  @param {Number} x - number to round
  @param {Number} n - power of 10 (integer)
  @returns {Number} rounded value