fixes #170
Invoice fix to make sure that overlapping full repair scenarii are correctly handled.
Added invoice specific unit test to verify that behavior (test testOverlappingRepair in TestSubscriptionItemTree)
Ported regression testRegressionFor170 in TestDefaultInvoiceGenerator
Added extra invoice generation in all beatrix tests to verify wach test end up in a stable state

Conflicts:
	beatrix/src/test/java/org/killbill/billing/beatrix/integration/TestIntegrationBase.java
	beatrix/src/test/java/org/killbill/billing/beatrix/integration/TestIntegrationInvoiceWithRepairLogic.java
fixes #170 (Hopefully this is time this is for real)

Modified assertion in test testRegressionFor170 so that it makes sense and fixes code to make sure the (correct) test pass.
The short story is that it is somehow complicated because we need to support cases where any form of existing invoices with any form
of billing events (forming the proposed events) should trigger a correct invoice.
Test timeout change