GL implementation - implemented Journal setup screens for error journal

[Jacopo Cappellato]

As a followup to the recent discussion about GL journals to group the 
failed accounting transactions, I've implemented the base screens to 
create/edit journals and to define the error journal in rev.597976
It is also possible to search for transactions and transaction entries 
by journal id.

The details are here:
http://docs.ofbiz.org/x/sgw

Jacopo