FlightPath 5.x-5.0-rc1

Referenced project: 
Release version: 
Release type: 
Bug fixes and new features
Release notes: 

Added new system setting, letting you disable logins for all but admin. Very helpful for
maintenance tasks.

Fixed bug in _FlightPath, causing errors.

Changed way I was forcing something to be numeric, to silence a warning in PHP 7.2

Fixed code which causes a bug in MySQL 8+

Added a new option to System Settings: enable or disable display level-3 selection on what if selection screen. If disabled,
this has more of a feel for FlightPath 4, and might help schools which do not allow dynamic degrees, or who have so many level 3
options that it causes confusion.

Fixed a left-over $this in db.inc, which caused problems in specific situations.

Fixed another SQL bug in the course_search module.

Fixed bug where outdated subs were being hidden. Had to do with the way the _Course.php file was checking for if a course
was substituted or not.

Fixed several bugs in db.inc's fp_get_degree_title() function, which was causing it not to work at all.

Modified the Administrator's Toolbox message so that outdated subs correctly state what degree they were from
which is now outdated.

Removed mysql_* functions from course_search module.