Try running script from working directory

[clubby789]

Fixes #234
If we have a non-absolute path that doesn't begin with ./, check for the script in the current directory and adjust the script path if it exists.

[ehuss]

Thanks for the PR! I'd love to get this fixed, as I often find it awkward to need ./.

[ehuss]

Thanks!

I suppose this will break if someone passes an executable from PATH, but I imagine 99% of the time that isn't the case. If that's an issue, we can revert or adjust as needed.