Fixes:
- Auto-comma the To: field when it loses focus
- Fix tick over selected emails
- Refine view email page
-- Delete/read/unread/move actions that don't break everything
- Improve network status page
-- Show full network error? Make it copy-able?

Tasks:
- Show logged-in status in persistent notification
- More layouts for intro and setup (tune for each screen size)
- Create and bundle better network status icons
- Subclass EmailListFragment for each default mailbox
- Refactor code
-- Reorganize for clarity
-- Optimize use of Android lifecycles

Features:
- Fingerprints that users can compare to validate
- Public address book lookup
- "Write email" link in address book
- Add optional CC: and BCC: fields
- Attachments
- QR codes for identities
- "Empty trash" option in Trash folder
- Overlay to explain
- Option to run only when connected to an outlet
- Option to run only when connected to wifi