redirect
packaging improvements

- py2app builds are now *much* closer to xcodebuilds
- dist command no longer creates a folder with supporting docs (since
they’re all bundled in the app now)
added gatekeeper code-signing
renovating the build dirs
threw away half of the build phases

- replaced the mess of copy-files phases with a single ditto from
setup.py’s build dir
- added a bytecompilation step (which will hopefully prevent any
gatekeeper problems from pyc files being generated later)
switched setup.py dist to use an xcode build