Merge pull request #315 from sortega/issue/110_refactor_order_controller

Move PeerInfo lookup from OrderActor to DefaultExchangeActor
Move order property updating to OrderActor

This is needed for preparing for order state persistence.
Merge pull request #316 from sortega/issue/110_refactor_order_controller

Move order property updating to OrderActor
Rename TransactionBroadcastActor and move it to a new package

Rename from TransactionBroadcastActor to ExchangeTransactionBroadcaster
to make it more clearly different than the actor broadcasting stuff
under BitcoinPeerActor.
Split ExchangeTransactionBroadcaster interface and implementation

And hide the implementation in its package
Remove StartBroadcastHandling.resultListeners

It is better to have those passed in the Props to avoid potentially
changing actor refs.
Initialize DefaultExchangeTransactionBroadcaster with a refund

And therefore, remove the initialization message.
This is done because the refund hash will be a good persistence id.
DefaultExchangeTransactionBroadcaster extends PersistentActor

But not yet persists events
Persist offers to broadcast
Extract broadcast policy to ExchangeTransactions

This simplifies the broadcaster actor (no multiple Receives).
Make DefaultExchangeTransactionBroadcaster fully persistent

Persist received offers and broadcast result.
Rename and add tests to ExchangeTransactions

Rename from ExchangeTransactions to BroadcastPolicy as it is more
important that it determines when and what to broadcast than its
attributes.

Split the test of DefaultExchangeTransactionBroadcaster into the
tests of the actor and the tests of the BroadcastPolicy.
Improve ImmutableTransaction.toString

Some incomplete bitcoinj transactions cannot be formatted as string
and, in that case, the exception should be captured.
Fix a corner case when watching for blockchain height

There was no notification in the case of watching an already happened
block until the next block was mined.
Merge pull request #317 from sortega/issue/113_persistent_exchange

Make exchange transaction publication persistent