Autocomplete email addresses in the composer from folks and the engine
This merge includes a few things:
- Include folks results in autocomplete listing
- Minor autocomplete UI tweaks
- Loads engine contacts by quering the database rather than loading them all up front (~50% total resident memory reduction for my three large accounts!)
- Only harvest contacts from mail in Inbox, Archive, Sent and normal folders (notably, not from Spam or Trash)
- Substantial other contact harvesting cleanup and bugfixing
See #133 (closed), #318