Cleanup Session::ObjectState
Cleanup Session::ObjectState

* Session::ObjectState::Forgotten is now a subclass of Session::ObjectState
* Use private instead of public visiblity

pvcarrera/rom,rom-rb/rom,pxlpnk/rom,kwando/rom,cored/rom,endash/rom,dekz/rom,Snuff/rom,rom-rb/rom,jeremyf/rom,rom-rb/rom,dcarral/rom,pdswan/rom,denyago/rom,vrish88/rom