MacOS Support

[Gunoshozo]

• Build as a .app bundle partially solved?? here & put static assets inside the bundle
• Add static assets platform independent path handling
• Put/look for dynamic assets (saves and editable assets) in more apropriate folders (e.g. Documents/Application Support) - can't be stored in the bundle
• Retina support??? Or maybe it can be covered by bicubic filter

Will update if something new comes up