Test account_invoice_sequence
[FIX] l10n_es_account_invoice_sequence: Asigna la misma secuencia para la factura y el asiento
[IMP] l10n_es_account_invoice_sequence: nueva API
[FIX] l10n_es_account_invoice_sequence: al cancelar y validar una factura se le asigna otro numero
l10n_es_account_invoice_sequence: with_context, quitar browse e 'internal_number' solo si se necesita
Merge pull request #62 from rlizana/account_invoice_sequence_test

[FIX] l10n_es_account_invoice_sequence: Problem when invoice is revalidated
[IMP] l10n_es_account_invoice_sequence: Tests