Past payment periods that have been paid against should be filtered from Multiple Payroll by default

[jniles]

Currently, all payment periods are listed as "open" and ready for payment in the Multiple Payroll (Indice) module. For example, here are the payment periods available at Vanga:

All payment periods prior to September should be closed, and users should not be able to pay against them. Ideally, when a payment period has transactions made against it, it should be filtered from this list to make it easier for users. Having them available means that users can still edit prior information, which may be problematic.