Feat/show trades profits

[syzygy800]

Here is an idea which could be added (and improved) to NEF. Implemented for Binance only. The purpose of it was to use it in a daily in a cronjob to generate data of the profits made. Some quick additions were made to make it useful from the commandline (here is of course much potential for improvment). Querying Binance for all made orders/trades is expansive in regardss to API costs. as the API doesn't offer it. In my R scripts I just query ALL markets for a given base currency.

Some things I want to point you to:

• in binance/client.go: the Orders function does now query every trade not only the last 500/1000(?). This has an impact of the rest of the NEF code.
• the commands name "trades" is more or less a working title. I am open for discussing it