improve `motion create` command by using optparse

Hi.
I often type `motion create --help` and motion goes like

```
meganemura:~/tmp$motion create --help
    Create --help
    Create --help/.gitignore
    Create --help/app/app_delegate.rb
    Create --help/Gemfile
    Create --help/Rakefile
    Create --help/resources/Default-568h@2x.png
    Create --help/spec/main_spec.rb
```

So, I modified codes not to create `--help` or `-h` directory anymore.

please consider to merge. thanks.