couple of suggestions for commissions

[Si Chen-2]

Hi all--

A couple of suggestions for commissions:
1.  A new agreement type for "Commissions" agreement.

2.  Default demo data set termDays to 30, so that the commissions  
invoices are due by default in 30 days.

3.  Modify the commissions services so if there is no termDays, no  
due date is set for commissions invoices.  This would be more  
consistent with the rest of invoices in OFBiz.  Currently, 0 days is  
assumed to be the default -- but that is not how the rest of invoices  
works, and not the default for most companies.

Si