Added missing features for document sending of invoices and creditmemos

Added missing features for document sending of invoices and creditmemos

No. of Emails:

in the sales documents and posted documents the no. of send emails information is added:

the no. of send emails is calculated over a background task and if you click on the no. send Mails the list of send mails is opened. With the restriction that you only can open the mails if you have the rights to do so. This can be setup in the email policy in the users page. 

There is also an action to open the send mails:

Sending Invoices/Credit memo: 

1. First of all we added the possibility again to add the BCC address. This can be setup in the wood setup page. 
2. With the new document sending profile there was no possibility to schedule the sending of the invoices/creditmemos. This now can be done in the wood setup: in the field Invoice/Credit Memo Send Time. If the value is empty the mails are send directly over the job queue otherwise we take te time that is setup in this field. 
3. The field Use Invoice address from is only useful for the reminders, to send invoice from a separate email address we can setup the following:
1. A specific email scenario for invoices and creditmemos and setup there a email address.
2. if we use responsibility centers we can setup there the used email account for invoices and creditmemos                                                    in the field replacement email address we can setup an other emailaccount for sending invoices.