Merge pull request #259 from sortega/issue/75_heisenbug

Try to fix heisenbug at BlockchainActor
Introduce OrderMatcher class

This class will be where the matching policy will be implemented.
Unnest Cross and refine its fields

A Cross is defined for exact amounts of net/gross to be exchanged.
Move order matching to OrderMatcher class
Decrease bid and ask amounts independently

As the net and gross bitcoin amounts of a cross are different, the
bid and ask orders should be adjusted by a different amount on handshake
success.
Merge pull request #260 from sortega/issue/81_matching

Extract order matching to a new class
Introduce StepwisePaymentCalculator

Introduce a class to deal with how to break down in steps the fiat
payment amounts and use it from DefaultAmountsCalculator.
Inject collaborators into OrderMatcher

Inject a SplitwisePaymentCalculator and a BitcoinFeeCalculator to be
able to compute crosses.

Also, make the cake wire the new collaborators.
Introduce orders in `CoinffeineNetworkProperties`

And inject it in `OrderController`
Make `OrderController` update peer orders
Replace binding source of order properties

Instead of react against Coinffeine app events, it reacts against the
`CoinffeineNetworkProperties` written by the actor system.
Extend usage of `AnyCurrencyOrder` into `CoinffeineNetworkProperties`

By replacing its own inner type alias `AnyOrder`.
Remove event publishing from `OrderActor`

And tune its tests to check whether it is updating the order properties as
expected.
Remove some unused entities for event processing

The last event types are removed from the codebase. The `EventPublisher` trait
is removed as well.
Base `NotificationManager` on properties instead of events

What leads to remove several classes related to event handling.
Add StepwisePaymentCalculator.requiedAmountToPay
Replace magic number 3 by HappyPathTransactions
Consider net and gross amounts when matching orders
Several minor fixes

* Use `AnyExchange` alias in `CoinffeineNetworkProperties`
* Fix illegible percentages in logged lines for `OrderActor`
* Move shorten order ID from `NotificationManager` to `OrderId`
Merge pull request #262 from sortega/issue/81_matching

Fix how orders are matched on the server