Fixes #834 (again)

PHP can't discern the difference between d/m/Y and m/d/Y when just the date
is submitted to strtotime(). Unfortunately, strptime() is not available
until PHP 5.1.0. This patch forces datepickers to change their values to
YYYY-MM-DD upon submission to disambiguate parsing issues.

Fixes #832

Previously the American date format (m/d/Y) was used exclusively for
formatting dates in the datepicker widget. This patch enables the widget to
be formatted based on the format set in the admin panel.

Fixes #829

The client and scp config ajax request only contain the settings for the
multi-file upload widget. So it doesn't need to be fetched unless the widget
exists on the page

Remove default max limit - no size limit is assumed.

Add overlay + please wait spinner on form submit

Remove obsolete functions

Impove row highlighter on table listing.

Add print options supports - staff can now print a ticket thread without internal notes + select paper size on the fly

Protect againts cross-site request forgery attacks by requiring a special
form-field or header to be sent with requests that modify ticket system
data.

This meant a slight change to the AJAX ticket locking mechanism. It was
defined to lock with a GET request; however, GET requests are defined as
safe methods and should not modify backend data (such as a lock
acquisition). Therefore, the the lock acquire AJAX method was changed to
require a POST method.

Also remove old, no-longer-used staff panel include files