Update version of Scala and dependencies
Enable another acceptance test
Merge pull request #142 from edrevo/general-update

Update version of Scala and dependencies
Merge pull request #143 from edrevo/enable-acceptance-test

Enable another acceptance test
Use OrderSet instead of Order as protocol message

Orders should be sent as a complete set to simplify the consensus of
the broker set. This means that Order is removed (thus a new Order
with less responsibility is kept). Consequentlyu, modify actors to use
OrderSet instead of Order.

Also, remove OrderCancellation message. The way to cancel an order is to send a new order set without that given order.

And finally, the removal of Order triggered a redesign of the Position class, that become templated (e.g. Position[Bid.type]), allowing the removal of several runtime checks in OrderBook and OrderMap.