function isCoprime( a, b ) {
	var v = gcd( a, b );
	if ( v !== v ) {
		return false;
	}
	return ( v === 1 );
}
Returns a boolean indicating whether two numbers are coprime.

@param {number} a - first value
@param {number} b - second value
@returns {boolean} boolean indicating whether the values are coprime

@example
var bool = isCoprime( 14.0, 15.0 );
// returns true

@example
var bool = isCoprime( 14.0, 21.0 );
// returns false