[FIX] purchase_analytic_plans: keep reference to analytic distribution

Purchase orders created with invoice policy 'Based on incoming shipments' were not keeping the reference to the account analytic distribution when invoiced. opw 607577
[IMP] account: do not offer closed analytic accounts on invoices

lp:1223922, opw 609656
[FIX] stock: do not set user_id on prepare_invoice_group

The user_id is already set by the prepare_invoice method, which is called before the prepare_invoice_group (the user_id is already set, thus)
Besides, _prepare_invoice is overriden in sale_stock, to set the picking sale order salesman as user_id, and, without this correct, grouping invoicse by partner re-set the user_id to uid, which is wrong.
[ADD] base_vat: add VAT validation for Peruvian localization.
[FIX] ir_fields: allow accent on selection import

If the selection label (not value) had accents, it wasn't possible to import it using the label having accents
[ADD] safe_eval: UNPACK_SEQUENCE and Exception

Allowing UNPACK_SEQUENCE allows the use of the "multi" assignation:
a, b = [1,2]
for a,b in items
[FIX] hr_holidays: do not allow reduce remaining leaves

In the Employee form, a remaining legal leaves field is available, which shows remaining validated leaves from allocation requests
As this is not allowed to delete a validated allocation requets, it shouldn't be possible to reduce the validated remaining leaves of an employee.
To reduce the remaining leaves of an employee, the user should cancel and remove the allocation request
[FIX] account: no journal items on consolidation accounts

As for the view accounts, the consolidation accounts should not allow to create journal items.
Fixes #1090
Revert 3dec090 "[FIX] ir_values: fallback when no condition"

An ir.value without condition should not match when searching with a condition.
When a field with change_default on it is modified, the method get_defaults is called with the new value. This means that manually modifying a field with this trigger would put back the default value (opw 611193).
[IMP] base_vat: differenciate VIES and classical VAT error

Display a different error message so that users are aware if the test failed with VIES enabled or not (opw 609823)