Added IsFiatCurrency function.
Added IsFiatCurrency function.

jmaurice/gocryptotrader,snipesjr/gocryptotrader,thrasher-/gocryptotrader,snipesjr/gocryptotrader,thrasher-/gocryptotrader,snipesjr/gocryptotrader,snipesjr/gocryptotrader,thrasher-/gocryptotrader,thrasher-/gocryptotrader,thrasher-/gocryptotrader,dolanor/gocryptotrader