Add project logo and use it for the app icon

- assets/logo.png (transparent) and assets/logo-256.png for the site
  and README
- tools/make_icon.m builds the full-bleed iOS icon from the logo

tools/build_native.py

@@ -96,14 +96,14 @@ def dylib(name, sources, defines=(), reexport=None, link_appkit=True, extra=()):
 
 
 def build_icon():
-    """Compile an asset catalog with the app icon, made from the game's own icon; returns plist keys."""
+    """Compile an asset catalog with the app icon, made from assets/logo.png; returns plist keys."""
     work = OUT / "icon"
     iconset = work / "Assets.xcassets/AppIcon.appiconset"
     iconset.mkdir(parents=True, exist_ok=True)
     tool = work / "make_icon"
     run(["xcrun", "clang", "-O2", "-fobjc-arc", ROOT / "tools/make_icon.m", "-framework", "Foundation",
          "-framework", "CoreGraphics", "-framework", "ImageIO", "-o", tool])
-    run([tool, GAME / "data/core/graphics/factorio-icon@2x.png", iconset / "AppIcon-1024.png"])
+    run([tool, ROOT / "assets/logo.png", iconset / "AppIcon-1024.png"])
     (iconset / "Contents.json").write_text(json.dumps({"images": [{"filename": "AppIcon-1024.png", "idiom": "universal",
         "platform": "ios", "size": "1024x1024"}], "info": {"author": "xcode", "version": 1}}))
     (work / "Assets.xcassets/Contents.json").write_text(json.dumps({"info": {"author": "xcode", "version": 1}}))