Introduce PollingTradeHistory.createTradeHistoryParams factory method
implement examples for ANX, Coinsetter and Hitbtc
createTradeHistoryParams fix types
make parameter types public, add constructors [ci skip]
Add default implementation of TradeService.createTradeHistoryParams
[Kraken] Implement parametrized TradeService.getTradeHistory
Switch to enum for contract, new futures impls
Inital commit for futures api
Renamed
Move FuturesPrompt to OkCoin and rename to FuturesContract
Separate Market,Trade,Account impls for Futures
Revert
Fixed okcoin test
Renamed OkCoinTradesDemo
Merge pull request #750 from jheusser/improveokcoinfutures

OkCoin: new API, Futures support
Introduce root interface TradeHistoryParams, getTradeHistory(TradeHistoryParams)
Merge branch 'develop' into feature/tradehist-factory

Conflicts:
	xchange-btctrade/src/main/java/com/xeiam/xchange/btctrade/service/polling/BTCTradeTradeService.java
[OkCoin] add getTradeHistory(TradeHistoryParams) throwing NotYetImplementedException
getTradeHistory(TradeHistoryParams): Bitfinex, Bitstamp; update interfaces and implementations
TradeHistoryParams fix errors
Unmatched Cryptsy pair

Changed from
UNKNOWN_UNKNOWN/USD
to
null/null

More accurately represents the unmatched currency pair