fixes #728
* updated API spec to inculde futuers trade and price examples
Corrected (!!!) this unit test. After the change of the timestamp datatype from flaot to BigDecimal in several DTO classes, the timestamp can now be read out exactly.
Changed the datatype of the timestamp field from float to BigDecimal. flaot is not able to represent the timestamp used by Bitfinex precisely.
Changed the datatype of the timestamp field from float to BigDecimal. flaot is not able to represent the timestamp used by Bitfinex precisely.
Changed the datatype of the timestamp field from float to BigDecimal. flaot is not able to represent the timestamp used by Bitfinex precisely.
Changed the datatype of the timestamp field from float to BigDecimal. flaot is not able to represent the timestamp used by Bitfinex precisely.
Changed the datatype of the timestamp field from float to BigDecimal. flaot is not able to represent the timestamp used by Bitfinex precisely.
Adapted this class to signature changes of several DTO classes regarding the timestamp datatype (changed from float to BigDecimal).
Created unit tests for the BitfinexAdapters class in order to verify its correct behavior regarding the timestamp conversion of BigDecimal (given by Bitfinex) to Date (as used in xchange).
Changed the datatype of the timestamp field from float to BigDecimal. float is not able to represent the timestamp used by Bitfinex precisely.
Changed indention to 2 spaces in order to adapt the existing coding style.
Changed datatype of Bitfinex' timestamps from float to BigDecimal since float led to a precision loss. Created tests to cover the changes.
Manually merged since there was an inconsistency between remote and local repository.
Manually merged since there was an inconsistency between remote and local repository.
#727: Introduce UserTrade
#727: add fees to HitBTC and VaultOfSatoshi user transaction history
#727: introduce and use UserTrades
#727: Use and test UserTrade(s) in tests
Fixed bug in adaptOrderType()

"buy" is not the server response.  It should be "bid".  Otherwise this method always returns OrderType.ASK
Changing trade.streaming.BTCChinaBalance.toString() method to be prettier.

Before, the method printed out a nasty string that prefixed the entire package name like:
com.xeiam.xchange...streaming.BTCChinaBalance@7f374, which is not a useful string.  The method is
now changed to behave like the toString() method in BTCChinaOrder of the same package.