support reading HSSFWorkbook with password passed as param

[pjfanning]

• relates to [Security/Bug] Clear-text Password Leak in Server Environments via Unmanaged ThreadLocal in Biff8EncryptionKey #1015
• also adds a setOutputPassword to HSSFWorkbook
• the old support for setting the read and write password using Biff8EncryptionKey is still supported too
• there are a lot of other changes need for issue 1015 but this is a start