* Partner balance (in standalone mode, without comparison):
the partners with a final balance of 0.0 were hidden,
they must be displayed because we need also, at least their initial balance,
so we can compare with the preceding year. The debit / credit can be useful too.
* All partners' reports:
we can not rely on the entries generated by OpenERP in the opening period for the parters,
so we force the computation of the initial balance based on the previous fiscal years.
(previously, we were displaying the entries of the opening period if there
was at least one, otherwise we were computing it).
* The computed initial balance was wrong when the opening period
of the very first fiscal year had entries.
The entries of the opening periods have to be excluded from the initial balances,
excepted for this case, because they do not have any counterpart the preceding year.
(lp:c2c-addons/6.1 rev 83)