Change method name to 中二病っぽい感じ
Devide servant methods about Language
Devide Lang methds to property `Servant.Lang`
Change initialize process of `Servant.Lang`
Add func `Lang.Have`
Add func `Lang.Is`
add func `Lang.Use` (with 2 issues :smiling_img: )
Memo for using options file
Add property `Servant.Options` and methods
Add `studyUp` for studying Golnag
Add general private method