Merge pull request #101 from sortega/remove-axis

Remove unused sbt-axis plugin
Remove unused test support class
Introduce TcpPortAllocator

To help allocating TCP ports for integrated tests avoiding tests
stepping on each other when opening server sockets.
Introduce PeerActor

Make QuoteTest fail because the peer doesn't process QuoteRequest
messages. Also, introduce some infrastructure for matching futures.
Move system package to coinffeine-common
Add parser of peer command line arguments
Introduce PeerSupervisorActor

To have a PeerActor and a ProtoRpcMessageGateway available on the
acceptance tests. Current failure on acceptance test QuoteTest:
cannot forward message QuoteRequest(EUR) to coinffeine://fake:4790/

This can be solved by having an actual broker on the acceptance tests.