Attempt to improve GC with weak references (not tested)
Added additional support for chest based GUI menu's
Fixed WeakReference usage in the UserManager, now actually works...
Though i have noticed that some objects does not get gc after a while which might be because of multiple reasons
one is the the garbage collector doesn't care because the test server got plenty of ram
the other and this is something it shouldn't, is that some plugin is holding the object that is set to be a weakreference