first commit
add function
add last function
refactoring
added last function
added all method
refactored setup method
refactored test class name
added removeFirst method
added removeLast method
added removeAll method
added swap method
refactored add method & add method test
refactored file load method
refactored load method, for which can specify filename.
added save method
refactored using temporary folder
corrected how to use temporary folder
modified save method
added append mode of add method