The sort function takes a list of Point objects and sorts them either
by their x or y coordinate using merge sort.
Also added a method set_random, that sets the coordinates to random
values and a method str, that returns the coordinates as string.
The module defines a LineSegment class that displays a line segment in
two-dimensional coordinate system. It is defined by a start- and an
endpoint. It also contains a method to calculate the length.
The point module defines a Point class, that displays a Point in a
two-dimensional coordinate system. An object of the class contains a x-
and y-coordinate and a setter and getter method for each at this point.
