Default -p option for CDQI tool

[patgoley]

If I run the tool without -p, I get compiler errors on my Entity conformance extensions. The errors state typealias CDQIAttribute must be public because it matches a requirement in protocol Entity. Works fine if I run with -p. Compiled using Xcode 8.3.2, Swift 3.1

[invoy-ghigley]

Yes, I've seen this problem myself. It only occurs when I use the auto-generated "invisible" model classes with Core Data. These classes seem to be public by default. Conversely, if you create a "visible" model class, this is internal by default, which means defaulting -p will give compiler warnings.

If we make -p default, we need to add a new flag to turn it off. I sometimes want to create "visible" model classes because I override methods such as awakeFromInsert.

Thoughts?

[invoy-ghigley]

I have no problem with public being the default, by the way. I suspect that most people will use the auto-generated "invisible" model classes, so this is a sensible default.

Maybe we need something like this:

cdqi --visibility internal Model
cdqi -v public Model # This is the default

We would leave the -p flag as an alias for --visibility public for backwards compatibility reasons, however, making it the default effectively renders it a no-op.

Does this sound reasonable?

[Revolucent]

@patgoley By the way, if you like this proposal, would you mind submiting a pull request? :)

[patgoley]

@Revolucent Absolutely, just wanted to get your thoughts first. Will submit one soon. Thanks!

[Revolucent]

@patgoley As I said in #54, I want to create another project for the cdqi tool and make you the maintainer, assuming it's a responsibility you want to take on. Then we'd alter the main CDQI readme with instructions for installing it as a gem.