Merge pull request #1 from hankintosh/fixes

Small fixes.
Went back to using mdb-export with "-I mysql" because the default CSV
style did not contain appropriate NULL values. This caused
mysqlimport to report warnings and use integer value 0 instead. To
increase performance, wrap the inserts using BEGIN..COMMIT commands.

Enclosed the "Lut+Zea" column in backticks in the sr22.sql file to
avoid parsing errors.