function boxcox1p( x, lambda ) {
	return addon( x, lambda );
}
Computes a one-parameter Box-Cox transformation of `1+x`.

@private
@param {number} x - input value
@param {number} lambda - power parameter
@returns {number} Box-Cox transformation of `1+x`

@example
var v = boxcox1p( 1.0, 2.5 );
// returns ~1.8627

@example
var v = boxcox1p( 4.0, 2.5 );
// returns ~21.9607

@example
var v = boxcox1p( 10.0, 2.5 );
// returns ~160.1246

@example
var v = boxcox1p( 2.0, 0.0 );
// returns ~1.0986

@example
var v = boxcox1p( -1.0, 2.5 );
// returns -0.4

@example
var v = boxcox1p( 0.0, -1.0 );
// returns 0.0

@example
var v = boxcox1p( -1.0, -1.0 );
// returns -Infinity