TODOs fixed segment.java
Update Main.java

Adapted the test to our new declaration of a segment
Update Ball.java

created method getMiddlePoint to get the center of teh ball
Updated main.java

add print
Updated MovingBall.java

Created the beginning of the play
Updated Point.java

Added getX and getY to get the abscissa and the ordered
Created Vector.java (extends Segment.java)
Updated RollingBall.java

Added intersect to test the intersection of a ball and a segment