Trade table: grouping modes and page subtotals

The trade review table has a new grouping mode control next to the existing time buckets. Switch between grouping by time (with the same day/week style granularity as before), instrument, or account. Time granularity only applies in time mode, which keeps the other modes simple.

At the bottom of each page you now get a subtotal row for PnL, commission, and size on the trades you are looking at right now, which makes paginated reviews much quicker to sanity-check.