Script Manager Allow Remote

Passing the following url

https://raw.githubusercontent.com/JohnSundell/Marathon-Examples/master/AddSuffix/addSuffix.swift

into the create task results in

Opening addSuffix.xcodeproj/

Example

$marathon create https://raw.githubusercontent.com/JohnSundell/Marathon-Examples/master/AddSuffix/addSuffix.swift
🐣  Created script at https://raw.githubusercontent.com/JohnSundell/Marathon-Examples/master/AddSuffix/addSuffix.swift
✏️  Opening addSuffix.xcodeproj/

The following makes sense but I think the boolean check might be too tricky to manage at this point. We might want to rework the script manager to ensure the following four tasks can throw more specific errors.