Merge pull request #234 from sortega/issue/39_serial_ex

Simplify OrderActor and related actor initializations
Move `BlockchainStatus` to the `model.bitcoin` package
Add a new `bitcoinNetwork` item to `CoinffeineApp` trait

It would represent the functionality of the Bitcoin network accessible through
the API.
Bind `ApplicationProperties.connectionStatusProperty` to API properties
Improve `Property` reactiveness

Make `onChange()` function return a `Cancellable` object that can be used to
cancel the handler. Also add a `when()` function that returns a future that
represents the matching of the condition passed as argument.
Introduce `CoinffeineNetworkProperties` in API
Make `ApplicationProperties.networkStatus` react against network properties
Some refactor in `CombinedConnectionStatus`

Rename it to simply `ConnectionStatus` and remove its dependency to `event`
package by using its own Bitcoin and Coinffeine network status case classes.
Remove unused `CoinffeineNetwork.status`

Since its replaced by Coinffeinet network properties.
Remove `BitcoinConnectionStatus`

And all infrastructure in the actors to retrieve it.
Remove the retrieval of Coinffeine connection status from actor system

Since the network properties have supersed its functionality.
Merge pull request #235 from apoloval/task/PropertiesLayer

Move connectivity data retrieval to properties
Add code for stubbing `AmountCalculator`s
Introduce OrderController class

It extracts lot of logic related to maintaining and updating the order
from the OrderActor that now specializes in communicating and supervising
other actors.
Merge pull request #236 from sortega/issue/39_serial_ex

Explode OrderActor into smaller classes
Extract DelegatedOrderFunds from OrderActor

This new actor implements OrderFunds, a trait encapsulating order funds
availability for the OrderController.
Merge pull request #237 from sortega/issue/39_serial_ex

Extract DelegatedOrderFunds from OrderActor