feat save common config file.
feat: save version number to config file.
refactor: Divide writing config file to opening and contents.
feat: Save graphic config file.
refactor: Don't return reference string of file name but return it directly.
style: Wrote comments for description of functions.
style: modify func name from "check" to "parse".
feat: Do comment out the flag of sorting stars.
fix: Returned a bool at func where it must return string.
feat: Escape config string.
feat: Save captions to config.
fix: Overwrote buttons' caption by old data.
feat: Save config only when used option --save.
Merge pull request #3 from bowkenken/option-saving

feat: Option saving.