This patch adds an 'email' format to ThreadBody::display() which allows
formatting the html/text bodies specifically for email. Previously, there
was ambiguity between the html view (which included inline image support and
clickable links) and the email view, which requires neither.

If the HTML ticket thread is disabled, outgoing emails will have a text
thread body placed inside an HTML template. The template and message are
then sanitized and converted to text. However, htmLawed will munge the white
space in the message before converting to text.

This patch disables sanitizing. I think it's fair to assume that the
template and the message by the client or agent have been properly sanitized
prior to sending out the email.

Change v1.8.2 to v1.9.0
Drop help tips for list properties

As suggested by: https://github.com/osTicket/osTicket-1.8/issues/755

The user should not have to step over it