FIXED: Crash when clicking on an empty CPTableView with variable row height.
FIXED: Crash when clicking on an empty CPTableView with variable row height.

Previously, clicking anywhere in an empty CPTableView with variable row height was causing a crash due to the code trying to find the latest cached row height. This patch adds a check to ensure the last cached row height is not nil.

cacaodev/cappuccino,koamac/Cappuccino,krodelin/cappuccino,FrankReh/cappuccino,cappuccino/cappuccino,enquora/cappuccino,daboe01/cappuccino,daboe01/cappuccino,mrcarlberg/cappuccino,FrankReh/cappuccino,enquora/cappuccino,deltaprojects/cappuccino,mrcarlberg/cappuccino,Rosch/cappuccino,AlexanderMazaletskiy/cappuccino,FrankReh/cappuccino,rgv151/cappuccino,krodelin/cappuccino,mrcarlberg/cappuccino,FrankReh/cappuccino,tancred/cappuccino,primalmotion/cappuccino,cappuccino/cappuccino,Dogild/cappuccino,mrcarlberg/cappuccino,deltaprojects/cappuccino,wangshijin/cappuccino,wangshijin/cappuccino,zittix/cappuccino,rgv151/cappuccino,AlexanderMazaletskiy/cappuccino,koamac/Cappuccino,Dogild/cappuccino,FrankReh/cappuccino,zittix/cappuccino,tancred/cappuccino,primalmotion/cappuccino,kidaa/cappuccino,cappuccino/cappuccino,Dogild/cappuccino,enquora/cappuccino,Dogild/cappuccino,zittix/cappuccino,Dogild/cappuccino,zittix/cappuccino,Dogild/cappuccino,Rosch/cappuccino,Dogild/cappuccino,Rosch/cappuccino,koamac/Cappuccino,cappuccino/cappuccino,primalmotion/cappuccino,zittix/cappuccino,cappuccino/cappuccino,mrcarlberg/cappuccino,Rosch/cappuccino,krodelin/cappuccino,enquora/cappuccino,cacaodev/cappuccino,tancred/cappuccino,tancred/cappuccino,krodelin/cappuccino,daboe01/cappuccino,kidaa/cappuccino,AlexanderMazaletskiy/cappuccino,mrcarlberg/cappuccino,tancred/cappuccino,enquora/cappuccino,Rosch/cappuccino,kidaa/cappuccino,koamac/Cappuccino,cacaodev/cappuccino,zittix/cappuccino,wangshijin/cappuccino,zittix/cappuccino,rgv151/cappuccino,krodelin/cappuccino,Rosch/cappuccino,cappuccino/cappuccino,tancred/cappuccino,deltaprojects/cappuccino,kidaa/cappuccino,wangshijin/cappuccino,cacaodev/cappuccino,krodelin/cappuccino,kidaa/cappuccino,cappuccino/cappuccino,cacaodev/cappuccino,wangshijin/cappuccino,mrcarlberg/cappuccino,Rosch/cappuccino,cacaodev/cappuccino,AlexanderMazaletskiy/cappuccino,koamac/Cappuccino,FrankReh/cappuccino,FrankReh/cappuccino,daboe01/cappuccino,krodelin/cappuccino,primalmotion/cappuccino,koamac/Cappuccino,cacaodev/cappuccino,rgv151/cappuccino,kidaa/cappuccino,rgv151/cappuccino,rgv151/cappuccino,deltaprojects/cappuccino,primalmotion/cappuccino,enquora/cappuccino,deltaprojects/cappuccino,deltaprojects/cappuccino,AlexanderMazaletskiy/cappuccino,daboe01/cappuccino,FrankReh/cappuccino,enquora/cappuccino,primalmotion/cappuccino,rgv151/cappuccino,mrcarlberg/cappuccino,wangshijin/cappuccino,primalmotion/cappuccino,AlexanderMazaletskiy/cappuccino,deltaprojects/cappuccino,daboe01/cappuccino,daboe01/cappuccino