[WIP] Script Xcode to add dependencies automatically

**NB: bad ideas** (and when I say that you know it means something)

There’s lots of stuff that we might eventually like to leave as Xcode’s job, or that we might want to interrogate Xcode about sooner or later. Generally that isn’t 0.1 stuff, maybe 2.0 or later, but I figured I’d take a stab at replicating some stuff I’d done in a TextMate bundle long ago and far away to interact with Xcode via AppleScript.

The intention here is that we’d be able to interrogate or control Xcode during e.g. project setup; this should never be a part of e.g. CI.

Broadly, my thinking is something like:

1. Add or select a workspace
2. Add dependencies into said workspace
3. Set the primary target to link the secondary ones
4. `xcodebuild`