Fix #127

Invoice calculation for nextBillingCycleDay is wrong when the bcd is greater than the last day of the current month on which we start the recurring
alogorithm to invoice each month. As a result for example, an account with a BCD set on the 31 but for which first invoice occurs in a month that
only has 30 days would always be invoiced from 30 -> 30  and not (30, 31, 31 -30, ...)