Completed work on parsing market data from Cryptsy.
Sealed ID classes to ensure no subclasses are created, which could cause problems such as incorrect comparisons.
Added documentation to Market class.
Added support for retrieving transactions from Cryptsy.
Added new TradeID class for holding the primary key of a trade.
Reworked string-like IDs to have a generic super-class.
Added initial structures for fetching market trades from Cryptsy.
Completed code to parse trades.
Added methods to test for trade equality, and to render trades to text.
Added test for trade loading from Cryptsy.
Added market and order ID to trades where applicable.