Update dependencies
Update minitest dependency to 5.0
Make #get_scripts work when the GIR data is valid

- Check if #get_scripts returns the correct response before trying to
  fix it
- Update to gir_ffi 0.6.2 to handle the #get_script return value
- Fix tests to handle GLib::SizedArray (or any enumerable) instead of
  Array
Prepare version 0.0.4 for release