MySQL: Distinguish between "notes" and "warnings" in strict mode

MySQL has "notes", which are reported as warnings but do not necessarily indicate a problem.  For example "CREATE TABLE IF NOT EXIST" returns a note if the table already exists.  This causes a failure if it is used in strict mode because it treats the note as a warning.  The mysql driver should (optionally?) check the level of the warning and  ignore "notes" instead of treating them as errors.
