Robustness on Mac and shared build system work

* Make it compile and not crash on Mavericks (fixes #20).
* Sort out zqcc Mavericks issues (fixes #19).
* Tweak earlier change to `BASE_CFLAGS`.
* Add a shortcut ‘freeze’ script.
* Edit README to reflect status of project.
* Minor clarification for PyGUI to build instructions.
* Added potential debug versions of *nix executables to .gitignore.
* setup.py reads the release number and name from the `release` file.
* Properly give icon to Mac .app bundle.