Delete LinkedList.h

Rewrite head file "LinkedList.h" .
Create LinkedList.h

Add the 2nd version of LinkedList.h.
Release note:
1. add function "IsCircular" which tells if there is a circle in a singly linked list;
2. rewrite the function which print a list. now the function can traverse a ring.
Merge pull request #4 from theLastTrain/lingkedlistheadfile

Lingkedlistheadfile