Update signature of NullContext::val().
Update signature of NullContext::val().

CakeDC/cakephp,davidyell/cakephp,ADmad/cakephp,elboletaire/cakephp,petteyg/cakephp,petteyg/cakephp,ndm2/cakephp,garethellis36/cakephp,petteyg/cakephp,dakota/cakephp,cakephp-fr/cakephp,garethellis36/cakephp,cakephp/cakephp,berrygoudswaard/cakephp,HavokInspiration/cakephp,nrother/cakephp,tenkoma/cakephp,nrother/cakephp,garethellis36/cakephp,CakeDC/cakephp,dakota/cakephp,ADmad/cakephp,thinkingmedia/cakephp,mvdriel/cakephp,davidyell/cakephp,CakeDC/cakephp,cakephp/cakephp,dakota/cakephp,cakephp/cakephp,ADmad/cakephp,ndm2/cakephp,thinkingmedia/cakephp,elboletaire/cakephp,tenkoma/cakephp,garethellis36/cakephp,mvdriel/cakephp,tenkoma/cakephp,berrygoudswaard/cakephp,cakephp-fr/cakephp,elboletaire/cakephp,mvdriel/cakephp,ndm2/cakephp,davidyell/cakephp,cakephp/cakephp,HavokInspiration/cakephp,dakota/cakephp,nrother/cakephp,tenkoma/cakephp,thinkingmedia/cakephp,petteyg/cakephp,ADmad/cakephp,mvdriel/cakephp,berrygoudswaard/cakephp,CakeDC/cakephp,ndm2/cakephp,cakephp-fr/cakephp,HavokInspiration/cakephp