Merge pull request #151 from apoloval/task/StartStopService

Make `CoinffeinePeerActor` a service actor
Add a convenience function `ServiceActor.askStart()`

This convenience function may be used to simplify the actor start ask pattern.
Turn `OkPayProcessorActor` into a service

And reorganize the `CoinffeinePeerActor` starting process to use ask pattern
to start the services.
Merge pull request #152 from apoloval/task/StartStopService

Turn `OkPayProcessorActor` into a service
Increase logging detail
Fix MatchError bug
Introduce transaction bytes for fee calculation
Introduce AmountsComponent
Use and inject AmountsComponent at OrderActor
Introduce ableToBuy on Peers at integration tests
Fix imports order
Add 0.0001.BTC as defaultTransactionFee val
Add test for DefaultOrderFundsCalculator
Merge pull request #153 from gotoalberto/bug/it_broken

Fix Exchange at integration tests
Fix `ConnectionTest`

Not it starts the Coinffeine app and then checks the network is connected.
Merge pull request #154 from apoloval/task/StartStopService

Fix `ConnectionTest`
Homogenize initialization messages for MessageGateway
Homogenize initialization responses for MessageGateway
Move ProtoMessageGateway to the service actor model
Initialize the message gateway as a service