killbill-aplcache

Implemented payment provider plugin registry

added copyright header

Implemented payment info and added payment error object

Introduced payment provider plugin mechanism

Added Either class

First test for interacting with the event bus

Added event bus test for different event type

update invoice ddl to use field() notation update invoice …

api to support retrieving unpaid invoices
update invoice api to support date filtering
invoice/entitlement integration
clean up typos in PlanPhase

invoice/entitlement integration

Merge branch 'inv-ent-integration' of github.com:ning/killbill …

into inv-ent-integration

Conflicts:
	api/src/main/java/com/ning/billing/entitlement/api/billing/DefaultBillingEvent.java