Missing feature, the Iteration is available only on the explicit currencies.

[liuggio]

Would be great to have the Iteration available also on the calculated currencies,
This test is broken now:

    public function testShouldReturnCHFDuringTheIteration()
    {
        $price = new Price(
            array('USD' => 5),
            array('USD/CHF 1.500')
        );

        $currencies = array();
        foreach ($price as $money) {  // Iteration!!
            $currencies[] = (string) $money->getCurrency();
        }

        $this->assertEquals(array('USD', 'CHF'), $currencies);
    }