When following a link from an email, if you are already signed in to the
help desk as a client, you should just be redirected to the new ticket.

Otherwise, if a decoded email name has a comma in it, for instance

From: =?utf-8?B?RnJ5ZGVubHVuZCBIeW3DuGxsZXIsIEJldHRpbmE=?=
    <bettina.frydenlundhymoller@domain.com>

The address list will be parsed incorrectly since the comma has an ambiguous
significance. Usually, the personal name would be quoted; however, since it
is encoded, there is no need to quote it.

Previously, the display of the button was incorrect and more than one button
might have been displayed.

htmLawed stripped/discarded <div> tags nested inside inline tags such as
<a>. The previous replacement engine would replace <img> tags with <div>
tags and would cause the HTML to be corrupted by htmLawed.

This patch uses <span> tags which have CSS rules to be displayed as
inline-blocks. This should stay truer to the normal sizing and placement of
the original <img> tag.

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