add coordinates validation to setPixel
add coordinates validation to setPixel

oliversalzburg/lwip,domosapien/lwip,mottx/lwip,unbornchikken/lwip,weareu/lwip,michaelBenin/lwip,antoinepairet/lwip,cocos-creator/lwip,mottx/lwip,EyalAr/lwip,neophob/lwip,neophob/lwip,cocos-creator/lwip,GrimDerp/lwip,GrimDerp/lwip,sanemat/lwip,unbornchikken/lwip,EyalAr/lwip,fireball-x/lwip,michaelBenin/lwip,lpicanco/lwip,domosapien/lwip,gimox/lwip,fireball-x/lwip,antoinepairet/lwip,unbornchikken/lwip,weareu/lwip,GrimDerp/lwip,MAMISHO/lwip,MAMISHO/lwip,mottx/lwip,michaelBenin/lwip,sanemat/lwip,lpicanco/lwip,fireball-x/lwip,MAMISHO/lwip,MAMISHO/lwip,cocos-creator/lwip,mottx/lwip,antoinepairet/lwip,domosapien/lwip,sanemat/lwip,lpicanco/lwip,lpicanco/lwip,fireball-x/lwip,antoinepairet/lwip,gimox/lwip,weareu/lwip,oliversalzburg/lwip,gimox/lwip,EyalAr/lwip,sanemat/lwip,neophob/lwip,cocos-creator/lwip,oliversalzburg/lwip,oliversalzburg/lwip,gimox/lwip,neophob/lwip,weareu/lwip,michaelBenin/lwip,unbornchikken/lwip,EyalAr/lwip,domosapien/lwip,GrimDerp/lwip