Reduce memory usage (spatial data is rare)

git-svn-id: http://h2database.googlecode.com/svn/trunk@5705 e6896862-9d19-0410-bfb3-e9fa5d50e656
Large result sets now always create temporary tables instead of temporary files.

git-svn-id: http://h2database.googlecode.com/svn/trunk@5706 e6896862-9d19-0410-bfb3-e9fa5d50e656