Merge pull request #153 from apoloval/issue/141

Shorten some currency amount expressions
Split PeerActor interface and implementation

To avoid cyclic dependencies with collaborator objects.
Make OrderSet handle merge amounts ordered at the same price

Introduce VolumeByPrice class to represent order volume as a map from
prices to volumes.
Implement order cancellation
Enable IT about order cancellation
Merge pull request #154 from sortega/feature/cancel_orders

Implement order cancellation
Move more code to new currency classes
More code migration to the new currency classes
Yet another migration to the new currency code
Bump bitcoinj to 0.11.3
Add missing `application-ci.conf` for the test module
Merge pull request #157 from sortega/feature/bump_bitcoinj

Bump bitcoinj to 0.11.3
PR feedback
Merge pull request #156 from edrevo/replace-currency-classes-take-4

Move more code to new currency classes
Make test derived from BitcoinjTest run sequentially

This is needed since we need to manipulate some bitcoinj global state
for the tests and that introduce race conditions between tests.
Remove inappropriate use of AnyExchangeInfo
Merge pull request #160 from sortega/bugfix/158

Remove inappropriate use of AnyExchangeInfo
Merge pull request #159 from sortega/bugfix/155_heisenbug

Make test derived from BitcoinjTest run sequentially
Replace all usages of `BtcAmount` by `BitcoinAmount`

All the places where `BtcAmount` type was used is refactored to
use `BitcoinAmount` instead.
Remove `BtcAmount class

`BtcAmount` is replaced by `BitcoinAmount` and no longer needed. We
can remove it definitely.