Avoid concurrency problems

git-svn-id: http://h2database.googlecode.com/svn/trunk@5431 e6896862-9d19-0410-bfb3-e9fa5d50e656
StreamStore bugfixes

git-svn-id: http://h2database.googlecode.com/svn/trunk@5432 e6896862-9d19-0410-bfb3-e9fa5d50e656
Prepare for improved memory housekeeping

git-svn-id: http://h2database.googlecode.com/svn/trunk@5433 e6896862-9d19-0410-bfb3-e9fa5d50e656
Bugfixes, trace

git-svn-id: http://h2database.googlecode.com/svn/trunk@5434 e6896862-9d19-0410-bfb3-e9fa5d50e656
Tests

git-svn-id: http://h2database.googlecode.com/svn/trunk@5435 e6896862-9d19-0410-bfb3-e9fa5d50e656