Improve AU region insertion to prevent duplicates

This update addresses issues added in later versions of Magento where the Australia regions were added to the core product. It should also improve situations where other extensions may have added the regions already as it will simply check if the regions exist in the database and not add them if so.

Add Auspost and eParcel shipping methods

Updates in this release are:

• Add Australia Post as a shipping method
• Add Australia Post eParcel as a shipping method
• Add import and export of the eParcel price table
• Add the ability to export eParcel orders