Made session's request countdown configurable by setting `Session.requestCountdown` config variable.
Made session's request countdown configurable by setting `Session.requestCountdown` config variable.

Removed unused Session class properties.

Closes #2078

ADmad/cakephp,petteyg/cakephp,ionas/cakephp,justinyost/cakephp,elboletaire/cakephp,ADmad/cakephp,petteyg/cakephp,ADmad/cakephp,timhoeppner/cakephp,cakephp/cakephp,burriko/cakephp,ndm2/cakephp,ndm2/cakephp,petteyg/cakephp,kumamidori/cakephp,bravo-kernel/cakephp,tenkoma/cakephp,nrother/cakephp,erikfig/cakephp,web-player/cakephp,berrygoudswaard/cakephp,eryw/cakephp,gmponos/cakephp,berrygoudswaard/cakephp,justinyost/cakephp,Phillaf/cakephp,dakota/cakephp,jeffblack360/cakephp,HavokInspiration/cakephp,davidyell/cakephp,yinhe007/cakephp,akintoey/cakephp,garethellis36/cakephp,kumamidori/cakephp,thinkingmedia/cakephp,erikfig/cakephp,CVO-Technologies/cakephp,berrygoudswaard/cakephp,cakephp-fr/cakephp,cakephp-fr/cakephp,jerems02/cakephp,dkarvounaris/cakephp,timhoeppner/cakephp,bravo-kernel/cakephp,davidyell/cakephp,mvdriel/cakephp,tgr0ss/cakephp,adopico/cakephp,timhoeppner/cakephp,CakeDC/cakephp,Phillaf/cakephp,khoimt/cakephp-study,burriko/cakephp,eboominathan/cakephp,yinhe007/cakephp,elboletaire/cakephp,ndm2/cakephp,cakephp-fr/cakephp,akintoey/cakephp,davidyell/cakephp,Phillaf/cakephp,Balachan27/cakephp,tenkoma/cakephp,adopico/cakephp,petteyg/cakephp,gmponos/cakephp,Balachan27/cakephp,kumamidori/cakephp,ndm2/cakephp,tisu2tisu/cakephp,cakephp/cakephp,burriko/cakephp,eboominathan/cakephp,mvdriel/cakephp,justinyost/cakephp,jeffblack360/cakephp,gmponos/cakephp,pbaire/cakephp,eryw/cakephp,cakephp/cakephp,dkarvounaris/cakephp,dakota/cakephp,CVO-Technologies/cakephp,elboletaire/cakephp,garethellis36/cakephp,Balachan27/cakephp,garethellis36/cakephp,yinhe007/cakephp,akintoey/cakephp,jjj117/cakephp,garethellis36/cakephp,dkarvounaris/cakephp,jerems02/cakephp,erikfig/cakephp,jjj117/cakephp,HavokInspiration/cakephp,jjj117/cakephp,HavokInspiration/cakephp,tenkoma/cakephp,web-player/cakephp,thinkingmedia/cakephp,cakephp/cakephp,mvdriel/cakephp,mvdriel/cakephp,bravo-kernel/cakephp,khoimt/cakephp-study,web-player/cakephp,nrother/cakephp,CakeDC/cakephp,ionas/cakephp,michaelze/cakephp,tgr0ss/cakephp,CVO-Technologies/cakephp,pbaire/cakephp,CakeDC/cakephp,dakota/cakephp,michaelze/cakephp,tisu2tisu/cakephp,nrother/cakephp,ADmad/cakephp,ionas/cakephp,khoimt/cakephp-study,CakeDC/cakephp,michaelze/cakephp,eryw/cakephp,pbaire/cakephp,adopico/cakephp,tisu2tisu/cakephp,tgr0ss/cakephp,tenkoma/cakephp,dakota/cakephp,thinkingmedia/cakephp,eboominathan/cakephp,jerems02/cakephp,jeffblack360/cakephp