Fix posibrain not turning off if no candidate

The reset proc was checking for the presence of a brainmob, while one
was created in the constructor. It should rather check the presence of a
key
comments out suethecake's gun due to having a weapon's ban
Merge pull request #2654 from Ravensdale/master

Custom item fix
Merge pull request #2652 from SkyMarshal/master

Fire fixes and improvements.  Note: May need fine tuning.
Add check forposibrain without brainmob

This should never happen, but check nonetheless.
Merge pull request #2653 from Jupotter/master

Fix for posibrain not turning off
Fix a wrong null check in posibrain

A wrong nullcheck that prevent posibrain searching for a player
Merge pull request #2656 from Jupotter/master

FIx posibrain unable to be started
Fixes the bug with Filters allowing insane overpressurization.