Include binstub for *nix in build artifacts

via @paulcbetts https://gist.github.com/paulcbetts/e8514a03c6c01d1677cb

``` bash
#!/usr/bin/env mono
## Make sure to chmod +x this file!

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

mono "$DIR/scriptcs.exe" $@
```
