enable Retina support

To enable retina support in your project go to main.mm. replace the standard line:

ofSetupOpenGL(1024,768,OF_FULLSCREEN);// 

with:

ofAppiOSWindow * iOSWindow = new ofAppiOSWindow();
ofSetupOpenGL(iOSWindow, 1024, 768, OF_FULLSCREEN);		
iOSWindow->enableRetina();