$_SESSION variable is flooded if session timeout disabled

If you use this module to prevent multiple sessions with the same account but don't use it to put timeout on user's sessions, the $_SESSION gets flooded over time. This is because the hook_boot function will append the timestamp of each page load onto the $_SESSION variable and the only functionality that does anything with the timestamps is behind an if statement.

If you simply throw the same if statement around the location in the hook_boot where the timestamps are appended, this issue is fixed as they aren't needed. I've attached a patch for this.