Updates: Put an instance of vertices class into the triangle class.
Updates: Implement Point struct as some function's return type.
Updates: Change the way of store the triangle information from normal arrays to vector<Int*>
Updates: Add find neighbour triangle function
Updates: Add vertex struct
Updates: Use vector to store vertices information in Vertices class
Updates: Finish the find neighbour triangles.
Bug fixed: Fixed the bug of return same triangles.
Merge pull request #5 from mrtoniliu/Task6

Some preparation of Part2