Reworking attachment creation methods
Reworking attachment creation methods

The methods are now as follows:

Zotero.attachment([attachment dicts], parentid=None)
Zotero.attachment_simple([filepath, … ], parentid=None)
Zotero.attachment_both([[title, filepath], … ], parentid=None)

- The parent Item ID is now optional in these methods
- If it is omitted, the attachments will be created at the top level
- All three methods now accept lists as their first argument
- Zotero.attachment_both() accepts a list of lists or a list of tuples

urschrei/pyzotero,DrGo/pyzotero