Test build for:
- Added manual config of IMAP/SMTP auth mech
- Added digest auth for contacts and calendars - #313
- Fixed IMAP/SMTP auto auth mech - #365
- Fixed glitch when rapid deleting messages
- Refactored to engine-level serialization
- Improved toast notification logic - #115
- Added states to fix unwanted message list reset - #348
- Improved CalDAV discovery - #363