Basic prefs window. It's a start!
Decent-enough preferences window.

The buttons (mostly) do things and it's not horrible.
Now just have to figure out a way to get people to see it.
Sending AX events to self off the main thread is not fun times.
Semantics
Add keyboard shortcut for showing preferences window.

Good enough for now until there's a menu bar item.

Fixes #12.
Preferences window responds to ⌘W
Copy NNKit into app bundle.

But it's not yet enough for the app to run standalone… what am I
missing?