Disable exchange pair with no volume

[Emzy]

We had a few times the problem that trading was halted on an exchange.
But we still used the price from that exchange pair to aggregate an average.
This ends in a wrong average exchange rate.

The pricenode needs to automatically stop using exchange rates that has no volume.

Poloniex right now:

[ghost]

The screenshot above from when the problem was happening shows a positive volume, so in this case the exchange rate would still be counted.

Do you have any suggestions on how to resolve this issue?

[Emzy]

It shows a volume of "0".
The volume or the timestamp of the last trade are the first things I can think of.
Alternatively an exchange rate that is off by more than ~2% or so could be automatically excepted.

[ghost]

We had a few times the problem that trading was halted on an exchange.
But we still used the price from that exchange pair to aggregate an average.
This ends in a wrong average exchange rate.

This bug was fixed by PR #19, can be closed.