Fix MainMenu.xib warning; use automatic style to adapt to OS X version
Fix MainMenu.xib warning; use automatic style to adapt to OS X version

diogocarneiro/SpriteBuilder,diwip/SpriteBuilder,diogocarneiro/SpriteBuilder,spritebuilder/SpriteBuilder,ZeusbaseGameWorkshop/SpriteBuilder,DNESS/SpriteBuilder,ZeusbaseGameWorkshop/SpriteBuilder,quicklyslow/SpriteBuilder,diwip/SpriteBuilder,quicklyslow/SpriteBuilder,diwip/SpriteBuilder,ZeusbaseGameWorkshop/SpriteBuilder,DNESS/SpriteBuilder,DNESS/SpriteBuilder,DNESS/SpriteBuilder,RobertPeng/SpriteBuilder,quicklyslow/SpriteBuilder,rraallvv/SpriteBuilder,RobertPeng/SpriteBuilder,RobertPeng/SpriteBuilder,rraallvv/SpriteBuilder,diogocarneiro/SpriteBuilder,eric-seekas/SpriteBuilder,ZeusbaseGameWorkshop/SpriteBuilder,rraallvv/SpriteBuilder,spritebuilder/SpriteBuilder,diogocarneiro/SpriteBuilder,diwip/SpriteBuilder,eric-seekas/SpriteBuilder,diwip/SpriteBuilder,diogocarneiro/SpriteBuilder,olegnaumenko/SpriteBuilder,quicklyslow/SpriteBuilder,diogocarneiro/SpriteBuilder,rraallvv/SpriteBuilder,olegnaumenko/SpriteBuilder,RobertPeng/SpriteBuilder,RobertPeng/SpriteBuilder,spritebuilder/SpriteBuilder,spritebuilder/SpriteBuilder,diwip/SpriteBuilder,eric-seekas/SpriteBuilder,olegnaumenko/SpriteBuilder,spritebuilder/SpriteBuilder,spritebuilder/SpriteBuilder,ZeusbaseGameWorkshop/SpriteBuilder,olegnaumenko/SpriteBuilder,DNESS/SpriteBuilder,eric-seekas/SpriteBuilder,eric-seekas/SpriteBuilder,quicklyslow/SpriteBuilder,RobertPeng/SpriteBuilder,ZeusbaseGameWorkshop/SpriteBuilder,olegnaumenko/SpriteBuilder,olegnaumenko/SpriteBuilder,eric-seekas/SpriteBuilder,DNESS/SpriteBuilder,rraallvv/SpriteBuilder