Improved error message formatting.

git-svn-id: http://h2database.googlecode.com/svn/trunk@4971 e6896862-9d19-0410-bfb3-e9fa5d50e656
TransactionStore: new persisted transaction state "committing".

git-svn-id: http://h2database.googlecode.com/svn/trunk@4972 e6896862-9d19-0410-bfb3-e9fa5d50e656
Support empty statements that just contains a comment.

git-svn-id: http://h2database.googlecode.com/svn/trunk@4973 e6896862-9d19-0410-bfb3-e9fa5d50e656
Documentation.

git-svn-id: http://h2database.googlecode.com/svn/trunk@4974 e6896862-9d19-0410-bfb3-e9fa5d50e656