Several small tweaks to the client user experience

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

ee91d179 introduced a slightly different
tracking system for detecting sessions. Instead of completely disabling the
session system for AJAX and cron requests, it detects if the session is new
or not based on the session_id() and existing data in the session backend.

However, the patch did not correctly determine if a session was new.
Instead, it flagged all session as existing. This patch fixes the detection
of existing session data so that AJAX and cron requests can operate without
writing session data to the backend.

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.

Fix date formatting issues

Reviewed-By: Jared Hancock <jared@osticket.com>
Reviewed-By: @hawkhead99

Fix several observed issues

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

If the advanced search dialog is up, avoid refreshing the page

pipe: Decode address lists names after parsing emails

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

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.

Conflicts:
	include/client/view.inc.php
	js/osticket.js

Fix munging of linked external images

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

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.

And use admin-defined site logo

Show properties config button if the form exists

Reviewed-By: Jared Hancock <jared@osticket.com>
Reviewed-By: @stf675