Debug run scheme

Not really a classic PR. I'll explain myself:

I tried today to find an easier (more 'automatic') way to work on/debug Alcatraz. Until now, I builded the plugin, exited Xcode, used kattrali's xcode-debug() function to attach lldb, restarted Xcode... Which is quite a cumbersome process.

It turns out that you can set Xcode to run a custom binary when using the "Run" scheme. I tried setting the Xcode app as the target, and it seems to work like a charm! For each run, Xcode spawn a new instance of itself, and attach lldb to the new process. So you can debug using Xcode's interface, as if you were debugging your own app (with breakpoints and all).

So not a real PR, as I have no intention of forcing everyone to use this method to debug, but I'd like to have a feedback on this. Did you already try that? Does it have any downsides?