Issue #216: Two accounts involving one conversion reported at cost (blais/beancount)

[Eduardo Villegas]

New issue 216: Two accounts involving one conversion reported at cost
https://bitbucket.org/blais/beancount/issues/216/two-accounts-involving-one-conversion

Eduardo Villegas:

In Beancount, you can have the following two transactions:

(1)
```
2018-02-14 * "On-line purchase"
Expenses:Clothing 10 USD
Expenses:Grocery 14 USD
Assets:Bank
```

(2)
```
2018-02-14 * "On-line purchase"
Expenses:Grocery 12 USD {}
Assets:Bank -10 EUR

```

However, you can't have:

(3)

```
2018-02-14 * "On-line purchase"
Expenses:Clothing 10 USD {}
Expenses:Grocery 14 USD {}
Assets:Bank -20 EUR
```

Use scenario: whenever you pay with credit card and the payment involves two or more accounts on one leg.

Beancount reports `Too many missing numbers for currency group 'EUR'`.

Of course, I can split the transaction if I make the proper calculations, but this way my journal will differ from the bank statements.