This module extends the functionality of Invoicing to support the
printing of customer and vendor statements. There are three types of
statements: Activity, Detailed Activity, and Outstanding. Aging details
can be shown in the reports, expressed in aging buckets, so the customer
or vendor can review how much is open, due or overdue.

The activity statement provides details of all activity on the partner
receivables or payables between two selected dates. This includes all
invoices, refunds and payments. Any outstanding balance dated prior to
the chosen statement period will appear as a forward balance at the top
of the statement. The list is displayed in chronological order and is
split by currencies.

The detailed activity statement is an extension of the previous
statement, and intends to explain the transactions that have happened
during the period, also providing with a Prior Balance section and an
Ending Balance section.

The outstanding statement provides details of all outstanding partner
receivables or payables up to a particular date. This includes all
unpaid invoices, unclaimed refunds and outstanding payments. The list is
displayed in chronological order and is split by currencies.
