added CurrencyTest::test_should_be_created_with_an_amount_and_a_currency_code
added CurrencyTest::test_should_be_created_with_an_amount_and_a_currency_code
implemented Currency class initializer w amt and curr_code
added Currency::should_equal_another_currency_object_with_the_same_amount_and_currency_code
implemented spaceship operator for Currency
implemented     c1 = Currency.new(1, USD)
implemented test_should_be_able_to_be_added_to_another_currency_object_with_the_same_currency_code
implemented additon on Currency
added test_should_be_able_to_be_subtracted_from_another_currency_object_with_the_same_currency_code
implemented - method on Currency
implemented DifferentCurrencyCodeError for +/- operators
added test_should_be_able_to_be_multiplied_by_a_Fixnum_or_Float_and_return_a_Currency_object
implemented multipication
test_should_be_created_with_a_Hash_of_currency_codes_to_conversion_rates