Add test code for the issue #23 (serialization problem to update subscription with add-ons).
Merge pull request #24 from oohira/issue-23-test

Add test code for the issue #23
[maven-release-plugin] prepare release recurly-java-library-0.2.0
[maven-release-plugin] prepare for next development iteration
subscription: support termination

This is a squash commit of pull request #25 with a few changes:

* fix imports
* fix failing test

Written-by: Omri Spector <omri.spector@gmail.com>
Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>