email: (Correctly) parse priority to priority_urgency

Reviewed-By: Peter Rotich <peter@osticket.com>

lock: Disable navigation warning if not using the lock feature

Reviewed-By: Peter Rotich <peter@osticket.com>

thread: Defer loading email header information

Reviewed-By: Peter Rotich <peter@osticket.com>

email: Use \n as the default line ending

Reviewed-By: Peter Rotich <peter@osticket.com>

email: Some bounce notices actually have rich content

Reviewed-By: Peter Rotich <peter@osticket.com>

Here's an example email structure:
```
multipart/mixed
 - multipart/report; delivery-status
   - multipart/alternative
     - text/plain
     - text/html
   - message/delivery-status
   - message/rfc822
```

The previous code would only find the body if the email main headers had:
Content-Type: multipart/report; report-type="delivery-status". In such a
case it would scan for a plain/text body.

This patch will scan for the usual body if the scan for the body as usual if
the report scan did not find anything.

Also, output errors to stderr when running API from the command line

It seems that most systems handle the newline character alone without a
problem; however, some systems cannot handle the standard CRLF line ending
at all.

The %ticket_email_info table needs an index on thread_id. This is done in
the `develop-next` branch; however, this patch helps alleviate performance
issues on the main branch until the `develop-next` branch is collapsed for
main line development.

search: Fix search for unassigned tickets

Reviewed-By: Peter Rotich <peter@osticket.com>

forms: Fix unset of all checkboxes on a form

Reviewed-By: Peter Rotich <peter@osticket.com>

collabs: Skip activity notice if collabs included in Cc header

Reviewed-By: Peter Rotich <peter@osticket.com>

alerts: Consider "alert assigned on new message"

Reviewed-By: Peter Rotich <peter@osticket.com>

i18n: Automate dns signature publishing for language packs

Reviewed-By: Peter Rotich <peter@osticket.com>

csv: Add UTF-8 BOM to export file

Reviewed-By: Peter Rotich <peter@osticket.com>

faq: Show proper internal/public category in drop-down

Reviewed-By: Peter Rotich <peter@osticket.com>

dashboard: Fix initial page load and stats pagination

Reviewed-By: Peter Rotich <peter@osticket.com>

kb: Add setting to enable only for authenticated clients

Review-By: Peter Rotich <peter@osticket.com>

search: Fix search on create date

Clear overdue on close

Reviewed-By: Jared Hancock <jared@osticket.com>

oops: Fix dropped custom data from API requests

Reviewed-By: Peter Rotich <peter@osticket.com>

filter: Trim match values when saving rules

Reviewed-By: Peter Rotich <peter@osticket.com>

Fixed typo

cdata: Drop ticket cdata on delete

Reviewed-By: Peter Rotich <peter@osticket.com>

files: Clear attachment box after posting a response

Reviewed-By: Peter Rotich <peter@osticket.com>

thread: Log remote IP for staff replies and notes

Reviewed-By: Peter Rotich <peter@osticket.com>

This also adjusts the logic internally to lookup the priority by the
priority_urgency field, which should be constrained to follow priority
precedence over the priority_id field.

Because CSV has no way of indicating a content character set, writing the
file with a Unicode byte-order mark is useful to declare the content in
UTF-8 encoding.