[IMP] account: bank statement reconciliation proposition:
- find a move line whose amount exactly matches the bank statement line amount even if it has no partner
- properly handle multicurrency
- if there's no exact match, look for a set of move line whose amount is <= to the statement line's amount
[FIX] stock: typo incomming -> incoming in demo & tests

I avoid to change external ids, in case some custom/community modules use it in their own tests