[WIP] Some improvements

- [x] Add `empty-cmd` argument
- [x] Add color in gaudi output
- [x] Use declared variables in templates
- [x] Check the current version to download new templates (fixes #47)
- [x] Use first linked container if custom `fastCgi` is not set for an Apache container
- [ ] Add an use case for each container/binary
- [ ] Add an `-h` option