Gregory Casamento

Additional changes to NSTreeNode (adding children at specific index paths) will be addressed in a separate PR. This one is big enough already and they belong mainly in NSTreeNode and...

Index insertion is working propertly... as is deletion. 

I am currently working on selection logic and refining some of the other methods since they are selection-based. Once that is done I believe this PR should be reviewed and...

It appears there is an adaptor between NSTableView and it's binding... ``` frame #2: 0x00007ff812b5bbf8 AppKit`-[NSBinder _setValue:forKeyPath:ofObject:mode:validateImmediately:raisesForNotApplicableKeys:error:] + 440 AppKit`-[NSBinder _setValue:forKeyPath:ofObject:mode:validateImmediately:raisesForNotApplicableKeys:error:]: -> 0x7ff812b5bbf8 : xorl %r13d, %r13d 0x7ff812b5bbfb : movq...

@fredkiefer Please take a look at this. This PR is quite sizable, so I think this is a good stopping point. The selection logic changes are done, the following things...

> I will need to spend more time on this to better understand the usages of the bindings. Understood. The included test shows the ones I was trying to support....

behavior of addChild: method is now consistent with macOS

@fredkiefer Please review again, if possible.

> Looks better but it is really to big to review at once. Could you break out some changes into a separate MR? I will take a look to see...

> Looks better but it is really to big to review at once. Could you break out some changes into a separate MR? I have been looking at how to...