Support Alternative Transports

[cretz]

I see that the only way to use this framework is to marry yourself to the Iron HTTP framework which is very unfortunate. It sadly seems to be baked into every corner from config expecting sockets to API-adding callbacks returning Iron handlers. I have another transport I would like to use. Is this project too far along to make a backwards incompatible changes like abstracting out to a transport (and transport config) trait?

[Maria-Nosyk]

Thank you for the issue. We are aware of it, however, we are considering a different solution. We intend to introduce some transport abstraction so that it should become an inner implementation detail of Exonum. Although the issue is not currently in progress, we believe it will be resolved in the mid-urgent perspective.