Storing available balance for Bitfinex

Added ability for users to retrieve the available balance instead of
simply ignoring it
Fix NPE in BTCChinaSocketIOClientBuilder: if no private data specified to subscribe, do not emit private event.
Merge pull request #714 from fenwulf/develop

Storing available balance for Bitfinex
Merge pull request #716 from sutra/develop

Fix NPE in BTCChinaSocketIOClientBuilder: if no private data specified to subscribe, do not emit private event.
Merge pull request #717 from ww3456/develop

Authenicated Poloniex trade history added support for currency pair "all" + Cryptsy trade time as UTC
Add rippleWithdrawal and rippleDeposit transaction types. XChange crashed without this if such transactions were present.