Improved profiling tools.

git-svn-id: http://h2database.googlecode.com/svn/trunk@5820 e6896862-9d19-0410-bfb3-e9fa5d50e656
MVStore compaction

git-svn-id: http://h2database.googlecode.com/svn/trunk@5821 e6896862-9d19-0410-bfb3-e9fa5d50e656