improved NULL's handling in INSERT OR REPLACE clause

git-svn-id: http://svn.svnkit.com/repos/sqljet@1276 06c6b4df-3a75-4b2a-9d74-3e57e8079485
improved INSERT OR REPLACE: replaces multiple rows to new one on indexes conflicts

git-svn-id: http://svn.svnkit.com/repos/sqljet@1277 06c6b4df-3a75-4b2a-9d74-3e57e8079485