Mark tickets overdue which have no SLA

If a ticket has a due date and does not have an SLA set, the ticket would
never transition to overdue. This patch addresses an SQL flaw preventing the
ticket from being transitioned.

Fixes #757
Support incorrectly labeled us-ascii charsets

Some email clients (names omitted to protect the innocent) advertise the
encoding as us-ascii when iso-8859-1 was really implied. This patch allows
the two charsets to be interchangable.
Consistently handle emails

Whether HTML ticket thread is enabled or not, consistently handle the
processing of the email bodies
Emit a backtrace on db_error logs
Merge pull request #770 from greezybacon/issue/us-ascii-not-really

Support incorrectly labeled us-ascii charsets

Reviewed-By: Peter Rotich <peter@osticket.com>
Reduce cost of deleting orphaned files

Previous explain included a nested sub-select, which exponentially increased
the count of the rows to be examined. This patch eliminates one layer of
nesting on the sub-select and dramatically increases the performance finding
orphaned files.

Fixes #773

References:
http://www.osticket.com/forums/forum/osticket-1-7-latest-release/troubleshooting-and-problems-aa/9446-version-1-7-much-slower-than-1-6
Support updating the source of the ticket

Fixes #772
Make Crypto::random() more reliable on Windows

This patch makes openssl the preferred source of random data on Windows and
will only use mcrypt_create_iv on PHP 5.3.7 and newer.

Fixes #771
Support non-standard port numbers for MySQLi

Validate port during installation

Add help information about the non-standard port number to the popup tips in
the install screen.

Support MySQL 'localhost' connections using a non-standard port number.
Ordinarily, MySQL will ignore the port setting on *nix systems if the host
is specified as 'localhost'

Implements/Fixes #769
add table prefix to places missing in the query
Use http::redirect(...) which exits on redirect.
Merge pull request #779 from protich/develop

Die on redirect

Reviewed-By: Jared Hancock <jared@osticket.com>
Merge pull request #19 from yakatz/patch-1

add table prefix to places missing in the query

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #18 from greezybacon/issue/db-error-backtrace

Emit a backtrace on db_error logs

Reviewed-By: Peter Rotich <peter@osticket.com>
Handle parsing email if Reply-To header is missing
Merge pull request #777 from greezybacon/issue/772

Support updating the source of the ticket

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #778 from greezybacon/issue/773

Reduce cost of deleting orphaned files

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #780 from greezybacon/issue/email-reply-to

Handle parsing email if Reply-To header is missing

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #776 from greezybacon/issue/771

Make Crypto::random() more reliable on Windows

Reviewed-By: Peter Rotich <peter@osticket.com>
Merge pull request #767 from greezybacon/issue/757

Mark tickets overdue which have no SLA

Reviewed-By:  Peter Rotich <peter@osticket.com>