This reworks the tabs CSS and javascript coding to be more flexible and to
support vertical tabs. (Bootstrap calls this stacked.) The javascript also
allows the URL to include the hash-tag of the last-clicked tab so that the
tab can be automatically shown when the page is reloaded.

to indicate the primary language expected for translatable content

The statistics module on the dashboard was using the incorrect query parameter
'stop'. This meant that the module was loading all tickets from the report start
date to the present day. This commit fixes this by using the 'period' parameter
instead.

This is necessary to avoid confusion vs. closed state.

Fix search backend to use the new statuses

Unify use of modal dialog
Make popup dialog graggable

Empty the popup container and show loading spinner
on-load hide the spinner and show the content

Delete tickets for realz when set to 'deleted' status. This commit will be
partially reverted once data retention plugin is added.

Move ticket status change to unified backend.

Ticket numbers are now configurable as a system-default and by help topic.
Previously, an administrator could select between six-digit random and
sequential numbers. Now, the sequence is selectable so multiple sequences
as needed, and a format can be specified to define how the ticket numbers
look. Formats can also be defined for each help topic.

pjax:complete is only called after an AJAX page load. If a user navigates
forward or backward and the page loads from local cache, then pjax:complete
is not fired. pjax:end, however, is always fired.

Add original and last message quotes to canned responses

The default mode going forward will be to insert when Rich Text support is
enabled and append otherwise. To clear the draft the user can simply click
reset or delete draft icon on the bar.

Enable delete draft option on reply & internal note boxes for consistency.