Add ability to retrieve all subscription transition from a Subscription
Add getOriginalAmount for invoice
analytics: more work, saving the current tree

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>
Merge remote-tracking branch 'origin/analytics-as-osgi-plugin-support' into analytics-as-osgi-plugin
analytics: fix 2 TODOs with latest code from analytics-as-osgi-plugin-support

Signed-off-by: Pierre-Alexandre Meyer <pierre@ning.com>