ref_price.txt

1. from script btsprice which used by witness
1) all MPA issued by commiittee
    "KRW", "BTC", "SILVER", "GOLD", "TRY",
    "SGD", "HKD", "RUB", "SEK", "NZD", "CNY",
    "MXN", "CAD", "CHF", "AUD", "GBP", "JPY",
    "EUR", "USD", "TCNY", "TUSD", "ARS"
2) some UIA issued by trusty gateway:
    "BTC": ["OPEN.BTC", "TRADE.BTC"], "USD": ["OPEN.USD", "OPEN.USDT"],
    "EUR": ["OPEN.EUR"], "CNY": ["OPEN.CNY"], "RUB": ["RUBLE"]}

2. from exchange poloniex.com
1) some UIA asset
    "OPEN.ETH", "OPEN.DASH", "OPEN.STEEM", "OPEN.MAID", "OPEN.LTC", "OPEN.OMNI", "OPEN.LISK", "OPEN.DOGE", "OPEN.GRC"
2) special SYMBOL can used in bots config page
    "POLONIEX:USDT_BTC"

3. all other asset's price are get from DEX's trade history with simple alg, 
   it's not trusted enough if the depth is bad, you'd better set a custom price for these assets.
   and there are no price from some assets, because they are lack of trade history