Writing to the trace file is now faster, specially with the debug level.

git-svn-id: http://h2database.googlecode.com/svn/trunk@5817 e6896862-9d19-0410-bfb3-e9fa5d50e656
Synchronize write access (needed for background compact operations), but avoid deadlocks.

git-svn-id: http://h2database.googlecode.com/svn/trunk@5818 e6896862-9d19-0410-bfb3-e9fa5d50e656
Improved MySQL compatibility by supporting "use schema". Thanks a lot to Karl Pietrzak for the patch!

git-svn-id: http://h2database.googlecode.com/svn/trunk@5819 e6896862-9d19-0410-bfb3-e9fa5d50e656