Add macos readme

Bundled/readme/readme_macos.txt

@@ -0,0 +1,13 @@
+ArmorPaint is currently an unsigned app. Due to security elements of macOS,
+you will not be able to run the .app out of the box. Depending on the error message,
+try one of the following.
+
+1.) "ArmorPaint.app is damaged and can't be opened."
+Open terminal in the unpacked ArmorPaint folder and type:
+xattr -cr ArmorPaint.app
+
+2.) "ArmorPaint can't be opened because it is from an unidentified developer."
+Open terminal and type:
+sudo spctl --master-disable
+
+Afterwards macOS should let you open the ArmorPaint.app file.

khafile.js

@@ -52,6 +52,10 @@ else {
 	project.addAssets("Bundled/readme/readme.txt", { notinlist: true, destination: "{name}" });
 }
 
+if (process.platform === 'darwin') {
+	project.addAssets("Bundled/readme/readme_macos.txt", { notinlist: true, destination: "INSTRUCTIONS.txt" });
+}
+
 if (process.platform === 'win32') {
 	project.addShaders("Shaders/voxel_hlsl/*.glsl", { noprocessing: true, noembed: false });
 }