- db_input now hadles arrays correctly.
- Code style cleanup..etc

And rearrange files to work with the new layout for the finalized upgrader

* Append page url to error alerts - useful in determining which page triggered the error.

Allow to upgrader to roll through tasks during upgrade without bread (trusting the tasks to break)

Add ticket class  (just incase the parent doesn't have it included)- required to fetch staff's ticket stats.

Add a (temporary) key to %ticket_thread allowing quick lookups on the old_pk
column. Also, only fill the temporary table used for linking responses to
the migrated messages with messages.

Remove clobber between queue() method and queue instance property (which is
the queue list). Also properly limit the number of attachments queued for
migration as indicated by the initial call to the queueAttachments() method.
Lastly, fix an issue where the first $limit items of the database cannot be
found on or read from the disk. Recurse through the queueAttachments()
method until the entire database is scanned or $limit items are placed in
the queue.

This overcomes the eventual limit of and database to support queries of a
finite length. We now split the file contents into 100k chunks and append
the chunks to the database one chunk at a time.

Migrate the PHP session from disk to database live. To pull this off, the
session contents are written to database under the current session id. When
the `ostversion` column is dropped from the %config table, the system will
automatically switch to database-backed sessions in osTicket 1.7 mode.

This is sort-of hacked together by carefully calling a instance method of
the osTicketSession class statically, and modify the instance method to
support static invocation.

When the `ostversion` column is removed from the %config table, the system
will immediately switch to database-backed sessions. Because the
administrator upgrading the system originally logged in with a file-based
session, it must be migrated to the database before removing the column.