* Remove tiles outside processing range. Useful when new content profile map
has different bounds.
* Remove ignored tiles. For a case when content profile maps have intersection
but there is no more data for navmesh.
* Remove older tiles at the same worldspace position. If navmesh tile data has
changed with new content, the old ones unlikely to be used.
* Vacuum the database when there are modifications. SQLite leaves empty pages
in the file on database modification. Vacuum cleans up unused pages reducing
the file size.
