[Bug 825538] [email/activesync] Need to allocate unique device ID's for multi-device access to ActiveSync.

Track observed device ids and be able to report them.

Some apparent sanity-checking logic I added in the past but never got around to
releasing.
Merge pull request #16 from asutherland/device-id

[Bug 825538] [email/activesync] Need to allocate unique device ID's for multi-device access to ActiveSync. r=squib
Force smtpd to reject an explicitly invalid email address.
Add option to force message sending to fail for all account types.
Add an option to create the default folders as subfolders of the inbox.
bump revision.