Add cask for Magic Number Machine.

[yacoob]

Adding a new cask

• Checked there aren’t open pull requests for the same cask.
• Checked there aren’t closed issues where that cask was already refused.
• When naming the cask, followed the token reference.
• Commit message includes cask’s name.
• brew cask audit --download {{cask_file}} is error-free.
• brew cask style --fix {{cask_file}} left no offenses.
• brew cask install {{cask_file}} worked successfully.
• brew cask uninstall {{cask_file}} worked successfully.

[vitorgalvao]

Thank you, but the app is discontinued, and we prefer to not add those in the official repos.

[yacoob]

"No new features" doesn't mean "discontinued". It's been working fine for me for all recent 10.x releases. If the application works, why not include it, it can always be removed when it breaks on a new OS release?