Convert Xcode project to ASCII (JSON-ish) format

Includes a script to throw an error if it gets converted back to xml

For reference, the script is

```sh
PROJECT_FILE="$PROJECT_FILE_PATH/project.pbxproj"

head -1 "$PROJECT_FILE" | grep -q '^<?xml'
if [[ $? -eq 0 ]]; then
	echo "Error: The Xcode project is in XML format. Run 'brew install xcproj; pod install'"
fi
```

I've tried uninstalling `xcproj` and running `pod install` and it'll just crash because the `xcodeproj` gem doesn't understand the ASCII format.