* Binance: implement get historic trades
* get binance trade data based on aggregate trade list
* fix small issue in rpc server: gctcli stops retrieving when there's
a gap in data
* update binance trade history availability in readme
* limit check batched aggregate requests
* add test for batched aggregated trades
* fix batch fromId query parameter
* update documentation
* send a serialised currency pair to GetAggregatedTrades
the rationale is that the API is kept generic so that callers can shoot
themselves in the foot if they want to
* allow requesting arbitrary limit of trades
* handle some error cases for batching GetAggregateTrades
* fix batch without end time
* don't return from batch too early if end time is not set
* additional check for supported limits
* don't use CheckLimits for GetAggregatedTrades
* the exchange doesn't use predefined valid limits for this request