v0.10.4 — Mac setup hotfix

A hotfix for the macOS setup. A setup downloaded with a browser could not get past "Preparing
setup files". Nothing in the game changed: it is v0.10.3, and only the Mac setup is different.

Changes

• Mac setup no longer stops on "python3" Not Opened
  (#59). After Install / Repair,
  macOS refused the Python bundled inside the setup ("Apple could not verify "python3" is free of
  malware…"), even when Def Jam Setup itself had been allowed with Open Anyway. The setup
  unpacked its files with the download's quarantine still on them, and macOS checks each of those
  files again. It now unpacks them without it. The files are the ones the setup already checks
  against its own checksum. You still allow Def Jam Setup once with Open Anyway, as before
  (the setup is not signed with an Apple Developer ID).
• For developers. tests/unit/test_macos_payload.py runs the setup's own unpack commands on
  a quarantined archive and checks that nothing stays quarantined.

Validation

• The owner installed from a test build of this setup on a Mac, after the browser-download
  quarantine had been applied to it. Setup got past "Preparing setup files" and installed.
• A setup with a quarantined payload unpacked 4,914 files with none quarantined, and its bundled
  Python, CMake and Ninja ran. Without the fix, every file (5,365 in v0.10.2) came out
  quarantined.
• Hosted CI builds and tests Windows, macOS and Linux. The game sources and the toolkit
  (32aab4d) are the same as in v0.10.3.

Known limits

• The v0.10.3 limits are unchanged; see known issues.

Updating

• Mac: download this setup if the v0.10.3 or earlier setup stopped on "python3". A
  Mac that already installed v0.10.3 has the same game and does not need to update.
• Windows and Linux: nothing changed. Updating installs the same game as v0.10.3.