- Adding new `IAlgorithm.AccountCurrency { get; }` that will point to the
`Portfolio.CashBook.AccountCurrency`. Setter will be added in a
following PR.
- Base `Brokerage` class will now have a `AccountCurrency { get }`
pointing to the `IAccountCurrencyProvider`. Will be used by the different
brokerages implementations.
In backtests with only a few insights (such as monthly), we end up never reaching
the warmup period and so we never chart the direction/magnitude scores.