Display Loading Overlay when posting a response or a note to a ticket.

* HTTP Option: TRUSTED_PROXIES (default: <none>
To support running osTicket installation on a web servers that sit behind a
load balancer, HTTP cache, or other intermediary (reverse) proxy; it's
necessary to define trusted proxies to protect against forged http headers.

* HTTP Option: LOCAL_NETWORKS (default: 127.0.0.0/24)
When running osTicket as part of a cluster it might become necessary to
white list local/virtual networks that can bypass some authentication
checks.

* Validate CLIENT_IP to make sure it's a valid IP address.

Encode html chars on helpdesk title

Ticket Filter Memory Leak

Task Duedate Timezone 

Defer to agent's timezone on due date `datetime` selection instead of
defaulting to GMT.

Fix case where filter applying 'Use Reply-To Email' filter action
triggers a reprocessing loop that exhausts php memory.

upgrader: Fix undefined function

Loading overlay

upgrader: Fix crash on SequenceLoader

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

Fixes missing due date on task create caused by invalid datetime format sent to db.

Use class instead of id on form element that triggers overlay on submit.

This checks to make sure string translation function '__()' is defined.

Passive Threading Revisited

Address cases where incoming email doesn't have message-id or references

thread: Fix crash processing problem attachments

Cleanup Client Ticket Table

1.10 :: Fix Last Updated variable for Help Topics

Passive Email Threading

v1.10-rc.3 Bug Fixes

Allow closed thread to be reopened when when is passive mode

Add support for threading email conversations happening outside the system.
Autoresponders are paused when threading is on passive mode. Alerts may
still go out to agents as configured.

Account for agents' name format setting when sorting agents.

MessageThreadEntry::add vs MessageThreadEntry::create

db_real_escape expects a string

Add department relationship to Canned model.

Fix bug brought about by commit #72e9abcf