function isInfinite( x ) {
	return Boolean( addon( x ) );
}
Tests if a double-precision floating-point numeric value is infinite.

@private
@param {number} x - value to test
@returns {boolean} boolean indicating whether the value is infinite

@example
var bool = isInfinite( Infinity );
// returns true

@example
var bool = isInfinite( -Infinity );
// returns true

@example
var bool = isInfinite( 5.0 );
// returns false

@example
var bool = isInfinite( NaN );
// returns false