Template is used for canned auto-reply - triggered by filters.

This will remove the upper limit of BLOB sizes imposed by MySQL with the
max_allowed_packet setting completely.

This adds a new table %file_chunk which will contain the filedata in smaller
chunks (256kB). It also includes a new class, AttachmentChunkedData, which
will handle reading and writing the data, abstracting away the chunks.

This is done by migrating data from the %file table to the %file_chunk
table. One must beware that this must safely (the migration that is) plug
into the both the live osTicket developers as well as the users doing a full
upgrade from osTicket-1.6*. For this, the AttachmentFile::save method was
patched to use the new AttachmentChunkedData class to write the attachment
data to the database in chunks. That is, the migrater will use the new code
on the major upgrade and bypass the filedata column of the %file table
altogether. Therefore, the patch associated with this commit will not
migrate any data for the major upgrade.

For developers doing incremental upgrades, the patch included in this
commit will transfer the data from the %file data to the new %file_chunk
table by chunking it. As written, only the first 16MB of the attachment is
migrated. This could easily be adjusted, but it seems like a reasonable
limit for now.

Force target selection on filter form
Add minor code improvements

* Change table name from ost_email_filter* to ost_filter*
* Add patch for target field.

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

Allow staff members the ability to select a default paper size which will be
used in printing tickets via PDF. In the future, this may be overridden per
ticket by a dialog box at print time.

Add the ability of revoking previous ticket state tracking events when new
events are logged for the same ticket. This will allow, for instance, the
ability to revert the 'closed' state of a ticket when the ticket is
reopened.

For statistics tracking, a user could configure whether or not the events
should be counted for each event tracked or just the non-annulled events.
For instance, if a ticket is closed and reopened several times, only the
very last closed event should count toward the statistics for the ticket.
Therefore, when a ticket is reopened, previous closed events should be
marked as annulled.