Imap-tools

* Fixed MailBoxFolderManager.list bug on delim = NIL

* Added MailMessage.size attribute

* Added MailBox.`__init__` starttls argument for using STARTTLS
* Fixed MailBox._fetch_in_bulk bug for empty self.search result

* Added BaseMailBox.search method
* Added BaseMailBox.fetch bulk argument
* Removed BaseMailBox._criteria_encoder
* Removed BaseMailBox.last_search_ids
* Added utils.grouper

* Added Attachment.content_id
* Added Attachment.content_disposition
* Attachment._part -> Attachment.part
* email.utils.parsedate_to_datetime used in utils.parse_email_addresses
* BaseMailBox.fetch limit argument now can receive slice object
* BaseMailBox instance now has attribute mailbox.last_search_ids, it fills after each fetch - msg ids from search command
* \_\_init__.py refined

* Added MailBox.xoauth2 - authentication using OAuth 2.0 mechanism
* MailMessage (to, cc, bcc, reply_to) now works for fields specified multiple times (e.g. twice Cc: Cc:)