Merge pull request #245 from sortega/issue/39_serial_exchanges

Make orders accepting partial matches
Add a new kind of property: the `PropertyMap`

This property models a thread-safe key-value store.
Merge pull request #246 from apoloval/task/cf-76

Add a new kind of property: the `PropertyMap`
Add `PaymentProcessorProperties`

And the corresponding support for cake pattern.
Inject payment processor properties into the corresponding actor

And make some code cleanup by grouping some actor arguments in case classes.
Make `OkPayProcessorActor` to use the properties to store the balances
Introduce payment processor properties in the app
Some cleanup in utilities for JavaFX properties
Add a new pimp-my-lib for `PropertyMap`

And clean its interface a little bit.
Make `ApplicationProperties` use the payment processor props

Instead of listening for events.
Remove useless class `FiatBalanceChangeEvent`

Which was completely replaced by payment processor properties.
Fix a bug that caused multiple order submitters to coexist

In some circumstances, the `MarketSubmissionActor` was spawning a new
submitter that coexisted with the last one before its death. This causes an
actor naming clashing and could derive in more serious problems when old and
new submitters fight to deliver its orders.

This commit fixes the problem by waiting for the previous submitter (if any)
to terminate before spawning a new one.
Merge pull request #248 from apoloval/fix/it

Fix a bug that caused multiple order submitters to coexist
Merge pull request #247 from apoloval/task/cf-76

Make payment processor use app properties instead of events
Handle another exchange cancellation cause
Rename OrderBookEntry.apply to fromOrder
Use gross amounts on AmountsCalculator
Support net/gross amounts on order matches

And make OrderMatch generic on the currency to force both fiat amounts
of the same currency. Modify also the serialization of the order match
message.
Merge pull request #249 from sortega/issue/39_serial_exchanges

Steps towards partial matching