function cabs( z ) {
	return hypot( real( z ), imag( z ) );
}
Computes the absolute value of a double-precision complex floating-point number.

@param {Complex128} z - complex number
@returns {number} absolute value

@example
var Complex128 = require( '@stdlib/complex/float64/ctor' );

var v = cabs( new Complex128( 5.0, 3.0 ) );
// returns ~5.83