Idea: We should optimize queries that use SORT followed by LIMIT.

The speed of queries with SORT + LIMIT is important, as it is often used to generate a presentation which has to fit in limited space, e.g. a screen.

The current implementation strictly searches, then sorts EVERYTHING FOUND, then returns the first LIMIT entries. We should change this to insertion during search into a sorted array / structure with room for only LIMIT entries. This can dramatically speed up SORT + LIMIT in cases where the search result is larger than LIMIT.