Update for Cocos2d 3.0

I have it working for Cocos2d 3.0 sample project, but I'm not exactly how to add legacy support. The legacy projects do not build with these changes. 

How do you recommend handling the API differences from 2.x to 3.x?

1. CCArray doesn't exist in 3.0 I think this can be safely used as a normal for loop on 1.x and 2.x 

        for(object in array)

2. userInteractionEnabled has been added to CCNode

    I'm not sure the best approach for adding backwards compatibility with the API change from 2.x to 3.x. I get build errors if I try to do this:

        if([self respondsToSelector:@selector(isRunning)]) {
             BOOL value = [self isRunning];
        }