Fix #40 - here string

We'll need to revise the build scripts. It's easier to run tests if we build as a folder under `Packages` than if we build as a `.sublime-package`.
Not very intuitive, but that's the list of excluded files for the `.sublime-package`. As I mentioned somewhere else, we should however revert to dir-based distribution (locally) for now. That way it's easier to run tests. I'll try to make the necessary changes in a separate PR.