Merge pull request #169 from sortega/issue/43_stalled

Fix issue 43 by limiting wallet changed notifications
Add connection reuse to ProtobufServerActor
Merge pull request #170 from edrevo/improve-message-sending

Add connection reuse to ProtobufServerActor
Increase the number of samples to avoid false alarms
Make CurrencyAmount invariant respect to its currency
Merge pull request #172 from sortega/fix_build

Increase the number of samples to avoid false alarms
Merge pull request #171 from sortega/covariance

Make CurrencyAmount invariant respect to its currency
Don’t check what the actors subscribe to directly

That is an implementation detail and should not be tested directly.
Remove also related matchers.
Use GatewayProbe on CoinffeineClientTest

It allow us to use delegates to handle message gateway received messages.
Extract counterpart’s refund signature logic to an actor
Merge pull request #173 from sortega/issue/30_handshake

Refactor tests to be able to delegate subscriptions to delegate actors