initial obj-c interface anti-quoter

I'm not sure if `iface` and `ifaces` are the best name.

But this adds some of the Anti quoters for `ObjCIfaceDecl`.

It is useful because I can do:
```objc
@interface AppWindow ()
$ifaces:props;
@property (readonly) typename NSView   *contentView;
@end
```

But unfortunately not because if you do:
```
[ciface|@property (strong) typename NSTextField *$q;|]
```
I can't find an anti quoter for `q`. I think this is an `ObjCIvarDecl`, then the `FieldGroup` inside of it. So a `ObjCIvarDecl` would be needed.