Abstract sort class includes abstract method "sort" and general methods isSorted, less, swap, print.
Selection sort is ready.
Insertion sort is ready.
Shell sort is ready.
Shell sort coefficient counting bug fix.
Merge sort is ready.
Quick sort is ready.
Now quick sort is really quick.
Added comment while methods are protected.
Fixed bug for equivalent elements in isSorted method.
Heap sort is ready.
Fixed step counting.
Final variant of test class.
Readme done.