[BITTREX] User trade history

-Full user trade implementation

-Optional parameter to specificy order book/public trades length

-Prepended "Bittrex returned an error: " when throwing
ExchangeExceptions
Fixed demo
Merge pull request #636 from zholmes1/develop

[BITTREX] User trade history
Updated with current symbol pairs

Added missing symbol pairs, removed old GHS NMC pair. (gives an error now)
Merge pull request #637 from Achterhoeker/patch-12

Updated cexIO with current symbol pairs
added timestamp to Bitfinex orderbook
added timestamp to Kraken orderbook
added timestamp to VoS orderbook
fix for previous updates with bug
[Bitfinex] Hidden orders
Merge pull request #1 from timmolter/develop

Update
Merge pull request #639 from zholmes1/develop

[Bitfinex] Hidden orders
Make Trades comparator static
[Bitfinex] Exception handling

All error messages returned by Bitfinex are now caught and thrown as an
ExchangeException with the message from Bitfinex.
[Poloniex] Account service exception handling

I will handle trade service exceptions once ResCU is able to parse
non-400 responses as an exception.
Merge pull request #641 from zholmes1/develop

Exception Handling
Merge pull request #640 from jheusser/static_comparators

Make Trades comparators static
[Bitfinex] Mute cancel order exception
Merge pull request #642 from zholmes1/develop

[Bitfinex] Mute cancel order exception
Crypto-Trade.com v2.0 API updates; CryptoTradeException; getTickers()