Filtering notifications doesn't grab more notifications

[craigmaloney]

Tootstream currently grabs al of the notifications for a user and then filters those notifications based on the flags passed by the user. Unfortunately this can cause instances where something where one can filter out the favorites, boosts, and follow requests and be left with only three mentions. What would be better is if the notifications would show more than one notifications-call's worth of notifications, up to a configurable level.