Remove reference to XoopsConnection
Recent change to security class resulted in two issues

First, the system should exit if an attempt to contaminate globals is detected, and that was removed. That functionality was re-added to the Xoops class that calls checkSuperglobals()

Second, the check for any string starting with 'xoops' has problems with things like 'XOOPS_TOKEN_REQUEST' which are required for normal use.

While looking at these issue, it seems the checks were case sensitive (based on array keys,) while PHP variables name are case insensitive. Fixed.
Not all event arguments are arrays.