Make this work with the Package Manager in Sublime 3

The `.no-sublime-package` file will make the package a loose package.

The problem is that ST3 stores package files per default in a single `.sublime-package`-file while ST2 stores the package files in directorys. The extension cannot execute scripts from inside the `.sublime-package` file. Thats why the `.no-sublime-package` is needed. The `.no-sublime-package` makes the package a loose package and all package files are stored in directorys again, like on ST2.