function cdf( x, p ) {
	return addon( x, p );
}
Evaluates the cumulative distribution function (CDF) for a Bernoulli distribution with success probability `p` at a value `x`.

@private
@param {number} x - input value
@param {Probability} p - success probability
@returns {Probability} evaluated CDF

@example
var y = cdf( 0.5, 0.5 );
// returns 0.5

@example
var y = cdf( 2.0, 0.1 );
// returns 1.0

@example
var y = cdf( -1.0, 0.3 );
// returns 0.0

@example
var y = cdf( NaN, 0.5 );
// returns NaN

@example
var y = cdf( 0.0, NaN );
// returns NaN

@example
// Invalid probability
var y = cdf( 0.5, 1.4 );
// returns NaN