Support formatting and parsing of money strings with currency code

[ryanskidmore]

It would be fantastic if this library supported the formatting and parsing of Money as strings with the currency code instead of symbol (e.g. USD 1.00) which eliminates any ambiguity caused by symbols being shared across currencies (e.g. $1.00 may refer to USD, AUD, CAD, etc).

This also enables the library to be used when storing money amounts in a database as a string, as these can be parsed when being retrieved instead of just being formatted when inserted.